Abstract: Five early restorer lines,including Minghui 2155,and five early CMS-lines,including Zhong 9A,were chosen for the study to understand their combining abilities on yield traits.A 5×5 incomplete diallele cross(NC-Ⅱ)design was employed.The results showed that the variances of the general combining ability(GCA)and the specific combining ability(SCA)were both highly significant on all characteristics.The genetic additive effects were found on the plot yield,panicles per plant,spikelets per panicle and 1000-grain weight(TGW).The characteristics were affected greatly by restorer lines,except seed setting rate(SSR)and TGW.The interaction between parents also played a significant role in SSR.Minghui 2155 had the greatest GCA effects on all yield traits.Among the cross combinations,Zhong 9A×Minghui 2155 showed the greatest SCA effects on yield in the plot test.