140 maize hybrids that were used in production in Jilin province at present were chosen and they were divided into eight groups,i.e.,early mature maize,middle mature maize,middle-late mature maize,late mature maize,tolerant to high-density maize,high oil maize,ensiling maize,specialization corn group.Three sites were selected in the half moist district of the middle part of Jilin province and in the semiarid district of the west of Jilin province.Maize unit weight of Jilin province was systematically studied and the difference of maize unit weight among different ecological area,different varieties was analyzed.Maize unit weight of each varieties was obtained and varieties which maize unit weight was higher that that of the control was selected.