Abstract: Genetic analysis for ear length, ear diameter, seed length,100 -grain weigth and yield per ear were conducted by using the method of components of means, two improved maize inbreds of PA group (J1255, J1401) were crossed with one tester(S122) witch traited by using six generations as materials. The results showed that the heredity of ear length and 100-grain weigth was dominated by additive affect, epistasis effect also existed significantly. The heredity of ear diameter, seed length and yield per ear were dominated by dominant effect, additive affect also existed significantly. The heredity of ear traits of all the crosses were dominated by epistasis effect. The additive effect of major genes for 100-grain weigth was greater than epistasis effect, and the dominance伊dominance was greater.