diff --git a/server/app/goauto/sybimport/apply.go b/server/app/goauto/sybimport/apply.go
index b4b021f..7acf7ab 100644
--- a/server/app/goauto/sybimport/apply.go
+++ b/server/app/goauto/sybimport/apply.go
@@ -100,6 +100,17 @@ func ApplyDetail(ctx context.Context, db *gorm.DB, order OrderInput, detail Deta
 			return err
 		}
 		if parsed.Status == models.SYBParseStatusSuccess && shopeeProduct != nil {
+			// `[必须]` 先消歧再入档。同一虾皮商品下 `黑色【短袖】` 与 `黑色【長袖】`
+			// 剥离后会塌缩成同一个 `黑色`，两个不同商品共用一份映射必然买错一半
+			// （#301）。消歧要看到同组全部原始规格，所以放在拿到 shopeeProduct
+			// 之后、写档案之前。
+			resolvedKeys, err := resyncShopeeProductKeys(tx, shopeeProduct.ID, rawProductSpecOf(rawJSON))
+			if err != nil {
+				return err
+			}
+			if resolvedKeys.Color != "" || resolvedKeys.Size != "" {
+				parsed.Color, parsed.Size = resolvedKeys.Color, resolvedKeys.Size
+			}
 			if err := mergeParsedSpec(tx, shopeeProduct.ID, parsed); err != nil {
 				return err
 			}
diff --git a/server/app/goauto/sybimport/reparse.go b/server/app/goauto/sybimport/reparse.go
index efdf1d0..d8de83a 100644
--- a/server/app/goauto/sybimport/reparse.go
+++ b/server/app/goauto/sybimport/reparse.go
@@ -80,6 +80,17 @@ func Reparse(ctx context.Context, db *gorm.DB, sybProductID uint64, force bool)
 		if parsed.Status == models.SYBParseStatusUncertain {
 			parsed.Status = models.SYBParseStatusFailed
 		}
+		// `[必须]` 重解析也要走消歧，否则它会把键写回剥离后的塌缩形式，悄悄
+		// 撤销导入时做的拆分（#301）。两条路径必须产出同一个键。
+		if parsed.Status == models.SYBParseStatusSuccess && record.ShopeeProductID != nil {
+			resolved, err := resyncShopeeProductKeys(tx, *record.ShopeeProductID, raw.ProductSpec)
+			if err != nil {
+				return err
+			}
+			if resolved.Color != "" || resolved.Size != "" {
+				parsed.Color, parsed.Size = resolved.Color, resolved.Size
+			}
+		}
 		outcome.NewStatus = parsed.Status
 
 		if parsed.Color == record.TargetColor && parsed.Size == record.TargetSize && parsed.Status == record.ParseStatus {
diff --git a/server/app/goauto/sybimport/resolve_keys.go b/server/app/goauto/sybimport/resolve_keys.go
new file mode 100644
index 0000000..0f12284
--- /dev/null
+++ b/server/app/goauto/sybimport/resolve_keys.go
@@ -0,0 +1,78 @@
+package sybimport
+
+import (
+	"encoding/json"
+
+	"go-admin/app/goauto/models"
+	"go-admin/app/goauto/sybspec"
+
+	"gorm.io/gorm"
+)
+
+// resyncShopeeProductKeys recomputes the purchase keys for every detail of one
+// Shopee product, including the one being imported, and writes back the
+// siblings whose keys changed (#301).
+//
+// `[必须]` 键的消歧需要同组全部原始规格，单条明细判断不了自己是否安全。新明细
+// 的到来可能让一个原本安全的键变成歧义——`黑色【短袖】` 独自存在时键就是 `黑色`，
+// 等 `黑色【長袖】` 进来才需要拆开。因此这里必须把兄弟明细一起重算并回写，否则
+// 同组内会出现一半旧键一半新键，比塌缩本身更难排查。
+func resyncShopeeProductKeys(tx *gorm.DB, shopeeProductID uint64, incomingRaw string) (sybspec.ParseResult, error) {
+	var siblings []models.SYBProduct
+	if err := tx.Where("shopee_product_id = ?", shopeeProductID).Find(&siblings).Error; err != nil {
+		return sybspec.ParseResult{}, err
+	}
+
+	raws := []string{incomingRaw}
+	rawByID := make(map[uint64]string, len(siblings))
+	for _, sibling := range siblings {
+		raw, ok := productSpecOf(sibling.RawJSON)
+		if !ok {
+			continue
+		}
+		rawByID[sibling.ID] = raw
+		raws = append(raws, raw)
+	}
+
+	resolved := sybspec.ResolveKeys(raws)
+
+	for _, sibling := range siblings {
+		raw, ok := rawByID[sibling.ID]
+		if !ok {
+			continue
+		}
+		keys := resolved[raw]
+		// `[必须]` 不碰人工或 AI 已确认的明细。它们的键是人（或经人确认的 AI）
+		// 定下的，消歧无权推翻——与 Reparse 不带 force 时跳过它们是同一条规则。
+		// 解析未成功的行同理，它们的键不由本函数决定。
+		if sibling.ParseStatus != models.SYBParseStatusSuccess ||
+			sibling.ManuallyConfirmed || sibling.AIConfirmed {
+			continue
+		}
+		if sibling.TargetColor == keys.Color && sibling.TargetSize == keys.Size {
+			continue
+		}
+		if err := tx.Model(&models.SYBProduct{}).Where("id = ?", sibling.ID).
+			Updates(map[string]any{"target_color": keys.Color, "target_size": keys.Size}).Error; err != nil {
+			return sybspec.ParseResult{}, err
+		}
+	}
+	return resolved[incomingRaw], nil
+}
+
+func productSpecOf(rawJSON string) (string, bool) {
+	var payload struct {
+		ProductSpec string `json:"productSpec"`
+	}
+	if json.Unmarshal([]byte(rawJSON), &payload) != nil {
+		return "", false
+	}
+	return payload.ProductSpec, payload.ProductSpec != ""
+}
+
+// rawProductSpecOf extracts the productSpec from an already-normalised raw JSON
+// payload, returning an empty string when it is absent.
+func rawProductSpecOf(rawJSON string) string {
+	raw, _ := productSpecOf(rawJSON)
+	return raw
+}
diff --git a/server/app/goauto/sybspec/resolve_keys.go b/server/app/goauto/sybspec/resolve_keys.go
new file mode 100644
index 0000000..0c18fa0
--- /dev/null
+++ b/server/app/goauto/sybspec/resolve_keys.go
@@ -0,0 +1,77 @@
+package sybspec
+
+import (
+	"strings"
+	"unicode"
+)
+
+// ResolveKeys turns every raw productSpec of one Shopee product into its
+// purchase keys, keeping a 【...】 annotation only where dropping it would make
+// two different specs collide (#301).
+//
+// 存在的理由：stripBrackets 无差别剥离 【...】，而括号里经常是商品本身而不是备注
+// ——`黑色【短袖】` 与 `黑色【長袖】` 剥离后都成了 `黑色`，档案里只有一个条目，
+// 两个不同商品共用同一份映射，必然有一半买错。#289 因此拦截，但人工匹配救不了：
+// 坏的是键本身。
+//
+// `[必须]` 消歧必须看到同一虾皮商品下的全部原始规格，单条明细无法独立判断
+// `黑色` 是否安全。因此这里接收整组，而不是逐条处理。
+//
+// `[必须]` 不塌缩的键必须与今天的行为逐字一致。线上一万四千多条明细里绝大多数
+// 不涉及塌缩，本次改动不能波及它们。
+func ResolveKeys(raws []string) map[string]ParseResult {
+	resolved := make(map[string]ParseResult, len(raws))
+	colorRaws := map[string]map[string]bool{}
+	sizeRaws := map[string]map[string]bool{}
+
+	for _, raw := range raws {
+		parsed := Parse(raw)
+		resolved[raw] = parsed
+		rawColor, rawSize := RawSpecHalves(raw)
+		collect(colorRaws, parsed.Color, rawColor)
+		collect(sizeRaws, parsed.Size, rawSize)
+	}
+
+	for raw, parsed := range resolved {
+		rawColor, rawSize := RawSpecHalves(raw)
+		if ambiguous(colorRaws, parsed.Color) {
+			parsed.Color = normalizeKey(rawColor)
+		}
+		if ambiguous(sizeRaws, parsed.Size) {
+			parsed.Size = normalizeKey(rawSize)
+		}
+		resolved[raw] = parsed
+	}
+	return resolved
+}
+
+func collect(index map[string]map[string]bool, key, rawHalf string) {
+	key, rawHalf = strings.TrimSpace(key), normalizeKey(rawHalf)
+	if key == "" || rawHalf == "" {
+		return
+	}
+	if index[key] == nil {
+		index[key] = map[string]bool{}
+	}
+	index[key][rawHalf] = true
+}
+
+// ambiguous reports whether more than one distinct raw half collapses onto key.
+func ambiguous(index map[string]map[string]bool, key string) bool {
+	return len(index[strings.TrimSpace(key)]) > 1
+}
+
+// normalizeKey drops every space so `黑色 【短袖】` and `黑色【短袖】` become the
+// same key.
+//
+// `[必须]` 必须整体去空白，不能只是折叠成单个空格：SYB 对括号前的空格写法并不
+// 一致，同一个规格的两种写法若被当成两个不同的原始值，就会被误判为歧义，把本来
+// 安全的键也拆开。归一后的形式同时用于比较和产出，两边一致。
+func normalizeKey(value string) string {
+	return strings.Map(func(r rune) rune {
+		if unicode.IsSpace(r) {
+			return -1
+		}
+		return r
+	}, value)
+}
diff --git a/server/app/goauto/sybspec/resolve_keys_test.go b/server/app/goauto/sybspec/resolve_keys_test.go
new file mode 100644
index 0000000..419c0d3
--- /dev/null
+++ b/server/app/goauto/sybspec/resolve_keys_test.go
@@ -0,0 +1,69 @@
+package sybspec
+
+import "testing"
+
+// `[必须]` 这是本单的核心用例。`【短袖】`/`【長袖】` 是商品本身而不是备注，
+// 剥离后塌缩成同一个 `黑色`，两个不同商品会共用一份映射（#301）。
+func TestAnnotationIsKeptWhenItDistinguishesTwoProducts(t *testing.T) {
+	short := "黑色【短袖】,3XL 【建議62.5-67.5公斤】"
+	long := "黑色【長袖】,5XL 【建議72.5-77.5公斤】"
+	got := ResolveKeys([]string{short, long})
+
+	if got[short].Color != "黑色【短袖】" || got[long].Color != "黑色【長袖】" {
+		t.Fatalf("颜色键未拆开: %q / %q", got[short].Color, got[long].Color)
+	}
+	// 尺码不塌缩（3XL 与 5XL 本就不同），必须保持剥离后的短键。
+	if got[short].Size != "3XL" || got[long].Size != "5XL" {
+		t.Fatalf("尺码键被误改: %q / %q", got[short].Size, got[long].Size)
+	}
+}
+
+// `[必须]` 不塌缩时必须与今天的 Parse 逐字一致，否则会波及线上绝大多数明细。
+func TestNonCollidingKeysAreUnchanged(t *testing.T) {
+	raws := []string{
+		"白色【短袖】,M 【建議42.5-47.5公斤】",
+		"藍色【短袖】,L 【建議47.5-52.5公斤】",
+		"香芋紫 【雙梅花】純棉,2XL 60.0-67.5公斤",
+	}
+	got := ResolveKeys(raws)
+	for _, raw := range raws {
+		want := Parse(raw)
+		if got[raw].Color != want.Color || got[raw].Size != want.Size {
+			t.Fatalf("%q 被改动了: 得到 %q/%q，应为 %q/%q",
+				raw, got[raw].Color, got[raw].Size, want.Color, want.Size)
+		}
+	}
+}
+
+// 同一个原始规格出现多次不算歧义——那只是同款重复下单。
+func TestRepeatedIdenticalSpecIsNotAmbiguous(t *testing.T) {
+	raw := "黑色【短袖】,M 【建議42.5-47.5公斤】"
+	got := ResolveKeys([]string{raw, raw, raw})
+	if got[raw].Color != "黑色" {
+		t.Fatalf("重复的同一规格不该触发消歧，得到 %q", got[raw].Color)
+	}
+}
+
+// 尺码侧同样会塌缩，规则必须对称。
+func TestSizeAnnotationIsKeptWhenItDistinguishes(t *testing.T) {
+	a := "黑色,均碼【薄款】"
+	b := "黑色,均碼【加厚】"
+	got := ResolveKeys([]string{a, b})
+	if got[a].Size != "均碼【薄款】" || got[b].Size != "均碼【加厚】" {
+		t.Fatalf("尺码键未拆开: %q / %q", got[a].Size, got[b].Size)
+	}
+	// 颜色两边相同，不该被消歧波及。
+	if got[a].Color != "黑色" || got[b].Color != "黑色" {
+		t.Fatalf("颜色键被误改: %q / %q", got[a].Color, got[b].Color)
+	}
+}
+
+// 括号前有无空格是 SYB 的不一致写法，不应产生两个不同的键。
+func TestWhitespaceBeforeBracketDoesNotSplitTheKey(t *testing.T) {
+	a := "黑色 【短袖】,M"
+	b := "黑色【短袖】,L"
+	got := ResolveKeys([]string{a, b})
+	if got[a].Color != "黑色" || got[b].Color != "黑色" {
+		t.Fatalf("同一规格的两种写法不该被当成歧义: %q / %q", got[a].Color, got[b].Color)
+	}
+}