In order to further improve the efficiency of maize composite population, four synthetic populations were crossed to four testers including Cpop.15, Cpop.16, W9706 and Si144 adopting NCII genetic design. The 16 crosses and one check hybrid Zhengdan958 were evaluated in Xinxiang of Henan province and Jinan of Shandong province to analyze the effect of introgression of different germplasm into maize composite population. The results showed an increase of grain yield in Cpop.15 and Cpop.16 after the introgression of different germplasm. The synthetic population CP15-2 exhibited short silking date, low plant height, low moisture at harvest and high grain yield, and good general combining ability (GCA) for day to silking and grain yield. The cross CP15-2 ×Cpop.15 showed better performance than the synthetic population Cpop.15 for day to silking, low moisture at harvest and grain yield, and low specific combining ability (SCA) effect and heteosis. Therefore, the synthetic population CP15-2 can be used as a new elite germplasm to improve the growth period, moisture at harvest and yield of the composite population Cpop.15.