Abstract: Abstract: Narrow germplasm base and shortage of fine germplasm resources have been the main problem in maize breeding of China. In order to breed out new self-bred line with higher disease resistance and stress resistance, exotic germplasm was utilized to improve the Chinese germplasms. The fine resistance genes were dug out and identified from the exotic germplasms and transferred to the Chinese germplasms by crossing. The offspring with resistant genes were screened out and backcrossed to get the purified germplasm. Finally, new self-bred line was bred up and used for the breeding of hybrids. Zhi 9831 was a new variety with prematurity character which bred up using the exotic resistance gene.