diff --git a/utils/compute.go b/utils/compute.go
index e85894b..71dcfe8 100644
--- a/utils/compute.go
+++ b/utils/compute.go
@@ -13,7 +13,9 @@ func ComputeIndividualIncomeTax(income float64) float64 {
 	}
 
 	// 实际纳税金额
-	income = income * 0.8
+	if income > 4000 {
+		income = income * 0.8
+	}
 
 	// 税率、速算扣除数
 	var taxRate, quickDeduction float64