diff --git a/components/form/style/index.less b/components/form/style/index.less
index 6484956267..51fa0a93ee 100644
--- a/components/form/style/index.less
+++ b/components/form/style/index.less
@@ -44,11 +44,13 @@
   }
 }
 
-.explainAndExtraDistance(@num) when (@num>=0) {
+.explainAndExtraDistance(@num) when (@num >= 0) {
   padding-top: floor(@num);
 }
-.explainAndExtraDistance(@num) when (@num<0) {
+
+.explainAndExtraDistance(@num) when (@num < 0) {
   margin-top: floor(@num);
+  margin-bottom: floor(@num);
 }
 
 // ================================================================