Abstract: Introduced the concept of genetic-the coefficient of coincidence to DUS Testing,the differentiation between maize standard varieties'expression was commented in Mengninggan ecoregion and test guidelines,which is in order to perfect the guidelines of maize and accumulate datum for constructing the DUS testing system of Mengninggan ecoregion.The results shows that the differentiation of COC was less than 0.05 except Danyu13,Benyu9,Huangzaosi,Shen5003 and P138;twelve resources'COC were 1 which is include CA335,F31,Huobai,Shennong92-67,8902,B73,DH14,X178,Wu314,Qi319,4F1 and Shen137.The COC of 8 measure traits were 1(Including Character26.1)and 2 measure traits less than 0.95(Including Character29.2).The other rest of the accord with coefficients was between 0.95 and 1;the COC of qualitative traits were greater than quantitative trait and 0.98.