A series of studies for improving the fertility of broiler breeders was conducted. The data on fertility came from 30 flocks, and approximately 90 000 sets of AA broiler breeders were statistically analysed and simulated by a computer. The emphasis of research was to expound some main factors that affect fertility -breeding period,sex ratio, body weight & constitution , leg & shank conditions, and house temperature. Integrated technical measures to raise the fertility of broiler breeders were worked out and recommended. Average fertilities of 90% under general production conditions and of 94% under ideal production conditions could be expected.