diff --git a/common.go b/common.go
index 0b0074e..dccf7c1 100644
--- a/common.go
+++ b/common.go
@@ -32,6 +32,10 @@ func RandRange(min, max int) int {
 	return rand.IntN(max+1-min) + min
 }
 
+func RandRangeFloat(min, max float64) float64 {
+	return min + rand.Float64()*(max-min+1e-10)
+}
+
 var (
 	getIpOnce  = &sync.Once{}
 	outBoundIp = "127.0.0.1"