diff --git a/gmtsph-regional.sh b/gmtsph-regional.sh
index 7d73dde..9b3976b 100755
--- a/gmtsph-regional.sh
+++ b/gmtsph-regional.sh
@@ -161,7 +161,7 @@ else
 	#-C${cptfile}+Uk 使用km（色标单位除1000
 	#如果unit等于km则在cptfile后面添加+Uk
 	if [[ ${unit} == 'km+Uk' ]]; then
-		gmt psscale -Dx${pagePara[1]}+w${pagePara[2]}+h -C${cptfile}+Uk -Bx${bartick} -By+l${unit} -O >> $psfile
+		gmt psscale -Dx${pagePara[1]}+w${pagePara[2]}+h -C${cptfile}+Uk -Bx${bartick} -By+l"km" -O >> $psfile
 	else
 		gmt psscale -Dx${pagePara[1]}+w${pagePara[2]}+h -C${cptfile} -Bx${bartick} -By+l${unit} -O >> $psfile
 	fi