The line style can be specified by using line option in symbol statement as showed below,


goption reset=all;

symbol1 i=j line=1 value=star color=red;
symbol2 i=j line=2 value=dot color=green;

data plotdata;
   do x=-5 to 5 by 0.1;
     pdfnormal1=pdf('normal',x,1);
         pdfnormal2=pdf('normal',x,1.5);
     output;
        end;
run;

proc gplot data=plotdata;
plot (pdfnormal1 pdfnormal2)*x/overlay;
run;
quit;

谢谢！