diff --git a/gmtsph-regional.sh b/gmtsph-regional.sh
index 437ad24..d2eceac 100755
--- a/gmtsph-regional.sh
+++ b/gmtsph-regional.sh
@@ -12,6 +12,7 @@ overwrite=0
 labels=("longitude (degree)" "latitude (degree)")
 plot_para=(0 0 0 0)
 plotgrad=0
+nocpt=0
 # 从命令行获取参数
 while getopts "hi:r:u:c:a:gv:" arg
 do
@@ -19,13 +20,14 @@ do
 		h)
 			printf "simple regional data mapping using GMT script. The template accepts a grid (.nc .grid) file as input and outputs a .png and a .eps file. \
 For futher explanations, please look for GMT's manuscripts.\nAuthor: Yi Zhang (zhangyi.cugwuhan@gmail.com)\n" 
-			printf "usage: ${0##*/} -i<grid-data> [-r<xmin>/<xmax>/<ymin>/<ymax>] [-u<unit>] [-c<cpt-file>] [-a<x-label>,<y-label>] [-g]\n"
+			printf "usage: ${0##*/} -i<grid-data> [-r<xmin>/<xmax>/<ymin>/<ymax>] [-u<unit>] [-c<cpt-file>] [-a<x-label>,<y-label>] [-g] [-n]\n"
 			printf "%s\t%s\n" "-i" "input grid file"
 			printf "%s\t%s\n" "-r" "data range. The template will ditect the input data range automaticly, the use of this option will overwrite the range."
 			printf "%s\t%s\n" "-u" "data unit. The default is meter."
-			printf "%s\t%s\n" "-c" "color cpt. The default is rainbow."
+			printf "%s\t%s\n" "-c" "color cpt. The default is rainbow. The script will use grd2cpt to recalculate the color scale file, use -n option to disable the use of grd2cpt."
 			printf "%s\t%s\n" "-a" "axis labels. The deafults are x (m) and y (m)."
 			printf "%s\t%s\n" "-g" "use grdgradient. The default is false."
+			printf "%s\t%s\n" "-n" "disabele the use of grd2cpt."
 			exit 0;;
 		i)
 			data=$OPTARG;;
@@ -40,6 +42,8 @@ For futher explanations, please look for GMT's manuscripts.\nAuthor: Yi Zhang (z
 			labels=(${OPTARG//,/ });;
 		g)
 			plotgrad=1;;
+		n)
+			nocpt=1;;
 		?)
 			printf "error: unknow argument\nuse -h option to see help information\n"
 			exit 1;;
@@ -86,7 +90,12 @@ else
 	COLOR_NAN=black \
 	MAP_LABEL_OFFSET=2.5p
 
-	gmt grd2cpt ${data} -R${range} -C${color} -Z -D -M > $cptfile
+	if [[ $nocpt == 1 ]]; then
+		gmt grd2cpt ${data} -R${range} -C${color} -Z -D -M > $cptfile
+	else
+		$cptfile = ${color}
+	fi
+
 	if [[ $plotgrad == 1 ]]; then
 		gradfile=usergradient.nc
 		gmt grdgradient ${data} -G${gradfile} -Nt -A0/45