diff --git a/backend/pkg/money/format.go b/backend/pkg/money/format.go
index ee223a4..e7c7dab 100644
--- a/backend/pkg/money/format.go
+++ b/backend/pkg/money/format.go
@@ -11,7 +11,35 @@ func Round(value float64) float64 {
 	return math.Round(value*10) / 10
 }
 
-// Min 返回两个金额中较小的值（角精度）
+// ToCent 将角转换为分（整数），用于存储
+// 12.3角 -> 123分
+// 12.34角 -> 123分（自动舍入到角）
+func ToCent(jiao float64) int64 {
+	return int64(math.Round(jiao * 10))
+}
+
+// ToJiao 将分转换为角（0.1元精度），用于API响应
+// 123分 -> 12.3角
+// 1234分 -> 123.4角
+func ToJiao(cent int64) float64 {
+	return float64(cent) / 10.0
+}
+
+// Format 格式化分为字符串（角精度，保留1位小数）
+// 123分 -> "12.3"
+// 1230分 -> "123.0"
+func Format(cent int64) string {
+	jiao := ToJiao(cent)
+	return fmt.Sprintf("%.1f", jiao)
+}
+
+// FormatWithSymbol 格式化分为带符号的字符串
+// 123分 -> "¥12.3"
+func FormatWithSymbol(cent int64) string {
+	return "¥" + Format(cent)
+}
+
+// Min 返回两个金额中较小的值（角精度，兼容旧代码）
 func Min(a, b float64) float64 {
 	if a < b {
 		return Round(a)
@@ -19,7 +47,7 @@ func Min(a, b float64) float64 {
 	return Round(b)
 }
 
-// Max 返回两个金额中较大的值（角精度）
+// Max 返回两个金额中较大的值（角精度，兼容旧代码）
 func Max(a, b float64) float64 {
 	if a > b {
 		return Round(a)
@@ -27,15 +55,18 @@ func Max(a, b float64) float64 {
 	return Round(b)
 }
 
-// Format 格式化金额为字符串（保留1位小数）
-// 例如：12.3 -> "12.3", 12.0 -> "12.0"
-func Format(value float64) string {
-	rounded := Round(value)
-	return fmt.Sprintf("%.1f", rounded)
+// MinCent 返回两个分值中较小的值
+func MinCent(a, b int64) int64 {
+	if a < b {
+		return a
+	}
+	return b
 }
 
-// FormatWithSymbol 格式化金额并添加货币符号
-// 例如：12.3 -> "¥12.3"
-func FormatWithSymbol(value float64) string {
-	return "¥" + Format(value)
+// MaxCent 返回两个分值中较大的值
+func MaxCent(a, b int64) int64 {
+	if a > b {
+		return a
+	}
+	return b
 }
diff --git a/backend/pkg/money/format_test.go b/backend/pkg/money/format_test.go
new file mode 100644
index 0000000..9a8e74c
--- /dev/null
+++ b/backend/pkg/money/format_test.go
@@ -0,0 +1,160 @@
+package money
+
+import "testing"
+
+func TestToCent(t *testing.T) {
+	tests := []struct {
+		name string
+		jiao float64
+		want int64
+	}{
+		{"12.3角转123分", 12.3, 123},
+		{"12.34角舍入到123分", 12.34, 123},
+		{"12.36角舍入到124分", 12.36, 124},
+		{"0.1角转1分", 0.1, 1},
+		{"0.05角舍入到1分", 0.05, 1},
+		{"0.04角舍入到0分", 0.04, 0},
+		{"100角转1000分", 100.0, 1000},
+		{"零值", 0.0, 0},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := ToCent(tt.jiao)
+			if got != tt.want {
+				t.Errorf("ToCent(%v) = %v, want %v", tt.jiao, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestToJiao(t *testing.T) {
+	tests := []struct {
+		name string
+		cent int64
+		want float64
+	}{
+		{"123分转12.3角", 123, 12.3},
+		{"1234分转123.4角", 1234, 123.4},
+		{"1分转0.1角", 1, 0.1},
+		{"10分转1.0角", 10, 1.0},
+		{"1000分转100.0角", 1000, 100.0},
+		{"零值", 0, 0.0},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := ToJiao(tt.cent)
+			if got != tt.want {
+				t.Errorf("ToJiao(%v) = %v, want %v", tt.cent, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestFormat(t *testing.T) {
+	tests := []struct {
+		name string
+		cent int64
+		want string
+	}{
+		{"123分格式化", 123, "12.3"},
+		{"1234分格式化", 1234, "123.4"},
+		{"10分格式化", 10, "1.0"},
+		{"1分格式化", 1, "0.1"},
+		{"1000分格式化", 1000, "100.0"},
+		{"零值格式化", 0, "0.0"},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := Format(tt.cent)
+			if got != tt.want {
+				t.Errorf("Format(%v) = %v, want %v", tt.cent, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestFormatWithSymbol(t *testing.T) {
+	tests := []struct {
+		name string
+		cent int64
+		want string
+	}{
+		{"123分带符号", 123, "¥12.3"},
+		{"1000分带符号", 1000, "¥100.0"},
+		{"零值带符号", 0, "¥0.0"},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := FormatWithSymbol(tt.cent)
+			if got != tt.want {
+				t.Errorf("FormatWithSymbol(%v) = %v, want %v", tt.cent, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestRound(t *testing.T) {
+	tests := []struct {
+		name  string
+		value float64
+		want  float64
+	}{
+		{"12.34舍入到12.3", 12.34, 12.3},
+		{"12.36舍入到12.4", 12.36, 12.4},
+		{"12.35舍入到12.4", 12.35, 12.4},
+		{"0.05舍入到0.1", 0.05, 0.1},
+		{"0.04舍入到0.0", 0.04, 0.0},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := Round(tt.value)
+			if got != tt.want {
+				t.Errorf("Round(%v) = %v, want %v", tt.value, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestMinMax(t *testing.T) {
+	t.Run("Min", func(t *testing.T) {
+		if got := Min(100, 200); got != 100 {
+			t.Errorf("Min(100, 200) = %v, want 100", got)
+		}
+		if got := Min(200, 100); got != 100 {
+			t.Errorf("Min(200, 100) = %v, want 100", got)
+		}
+	})
+
+	t.Run("Max", func(t *testing.T) {
+		if got := Max(100, 200); got != 200 {
+			t.Errorf("Max(100, 200) = %v, want 200", got)
+		}
+		if got := Max(200, 100); got != 200 {
+			t.Errorf("Max(200, 100) = %v, want 200", got)
+		}
+	})
+}
+
+// 测试双向转换的精度
+func TestRoundTrip(t *testing.T) {
+	tests := []struct {
+		name         string
+		originalJiao float64
+		expectJiao   float64 // 因为角精度，可能会有舍入
+	}{
+		{"12.3角往返", 12.3, 12.3},
+		{"12.34角往返（舍入）", 12.34, 12.3},
+		{"100.0角往返", 100.0, 100.0},
+		{"0.1角往返", 0.1, 0.1},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			cent := ToCent(tt.originalJiao)
+			gotJiao := ToJiao(cent)
+			if gotJiao != tt.expectJiao {
+				t.Errorf("往返转换：%v角 -> %v分 -> %v角, 期望 %v角",
+					tt.originalJiao, cent, gotJiao, tt.expectJiao)
+			}
+		})
+	}
+}