diff --git a/util.go b/util.go
index 93fbf6c..a92d82c 100644
--- a/util.go
+++ b/util.go
@@ -29,6 +29,12 @@ func FormatCNY(amountStr string) string {
 		return ""
 	}
 
+	// 处理负数
+	negative := amount < 0
+	if negative {
+		amount = -amount
+	}
+
 	var value float64
 	var unit string
 
@@ -48,6 +54,10 @@ func FormatCNY(amountStr string) string {
 	s := strconv.FormatFloat(value, 'f', 2, 64)
 	s = strings.TrimRight(s, "0")
 	s = strings.TrimRight(s, ".")
+
+	if negative {
+		s = "-" + s
+	}
 	return s + unit
 }