diff --git a/go/internal/governance/governance.go b/go/internal/governance/governance.go
index 0fc2c8a..60c5268 100644
--- a/go/internal/governance/governance.go
+++ b/go/internal/governance/governance.go
@@ -6,6 +6,7 @@ import (
 	"strings"
 	"sync"
 	"time"
+	"unicode"
 )
 
 // ─── 冲突检测 ────────────────────────────────────────────
@@ -95,27 +96,83 @@ func toStringSlice(v interface{}) []string {
 	return nil
 }
 
+// containsNegCN 检查文本中是否含中文否定词或单字否定
+func containsNegCN(text string) bool {
+	negPhrases := []string{"不是", "没有", "不存在", "禁止", "不允许", "无", "非"}
+	for _, n := range negPhrases {
+		if strings.Contains(text, n) {
+			return true
+		}
+	}
+	for _, r := range text {
+		if r == '不' || r == '没' || r == '莫' || r == '别' {
+			return true
+		}
+	}
+	return false
+}
+
+// splitWordsCN 中文按字符级切分（过滤标点），英文按空格分词
+func splitWordsCN(text string) []string {
+	if len(text) == 0 {
+		return nil
+	}
+	hasCN := false
+	for _, r := range text {
+		if unicode.Is(unicode.Han, r) {
+			hasCN = true
+			break
+		}
+	}
+	if hasCN {
+		var result []string
+		for _, r := range text {
+			if unicode.Is(unicode.Han, r) || (r >= 'a' && r <= 'z') || (r >= 'A' && r <= 'Z') || (r >= '0' && r <= '9') {
+				result = append(result, strings.ToLower(string(r)))
+			}
+		}
+		return result
+	}
+	return strings.Fields(strings.ToLower(text))
+}
+
+// IsContradiction 检查两条内容是否语义矛盾
+// 中文/混合文本：字符级重叠 + 否定词差异
+// 英文/空格文本：单词级重叠（原有逻辑）
 func IsContradiction(a, b string) bool {
-	// 简单启发式：重叠词 > 50% 但存在否定词差异
-	wordsA := strings.Fields(strings.ToLower(a))
-	wordsB := strings.Fields(strings.ToLower(b))
+	wordsA := splitWordsCN(a)
+	wordsB := splitWordsCN(b)
 	setA := make(map[string]bool)
 	for _, w := range wordsA {
 		setA[w] = true
 	}
-
 	overlap := 0
-	negInA := containsNeg(wordsA)
-	negInB := containsNeg(wordsB)
+	negInA := containsNegCN(a)
+	negInB := containsNegCN(b)
+	negInWordsA := containsNeg(wordsA) // 英文否定
+	negInWordsB := containsNeg(wordsB)
+
+	if negInA != negInB || negInWordsA != negInWordsB {
+		// 有否定词差异，再检查重叠度
+	} else {
+		// 无否定词差异，直接返回 false
+		return false
+	}
 
 	for _, w := range wordsB {
 		if setA[w] {
 			overlap++
 		}
 	}
-
-	totalOverlap := float64(overlap) / math.Max(float64(len(wordsA)), float64(len(wordsB)))
-	return totalOverlap > 0.5 && negInA != negInB
+	maxLen := len(wordsA)
+	if len(wordsB) > maxLen {
+		maxLen = len(wordsB)
+	}
+	if maxLen == 0 {
+		return false
+	}
+	// 阈值 0.3（中文字符级粒度细，0.5 过高）
+	return float64(overlap)/float64(maxLen) > 0.3
 }
 
 // DetectContradiction 检查 newContent 是否与 existingContents 中任意一条矛盾