Abstract: [Objective and Method]The early maturing maize inbred lines have been tested in this paper with the designing Zign of P1×P2 incomplete diallel crossing of NCⅡ method to study combining ability of 11 traits.Ana1ysis of the general combining ability showed that 11 traits was significantly difference.The special combining ability of 11 traits had significant difference.[Result]The result indicated that the lines of Wu314,Xinzi349,Xinzi3113-1 and ZPA82/9 had higher general combining ability (GCA) of yield per plant., the lines of Xinzi3112,Xinzi3119 and Xinzi4202 must be modified before application,the line of Xinzi3113-1 can be directly used but the traits of plant height and ear seat of it must be controlled by plant height and ear height.There were great effect value of negative combining ability of bare tip of ZPA82/9,Wu314 and Xinzi349 .The line of Zao314L had great negative effect value of combining ability and plant height.[Conclusion]The combinations of Xinzi3113-1×OS87-24,Xinzi3112×L02,Xinzi3119×Zao314L,Xinzi3112×Wu314,Xinzi4202×Xinzi349 and Xinzi4202×ZPA82/9 had special combining ability(SCA) of high yield per plant.