Abstract: In order to explore the change rules of ovarian follicles in Rugao yellow chickens at different laying periods, by selecting the Rugao yellow chickens at the prelaying period (16 wk of age), the early laying period (20 wk of age), peak egg-laying period (27 wk of age), and the telophase of laying (64 wk of age), the statistics of the weight of oviduct, the ovarian weight, and the number of pre-hierarchical follicles were carried out. At the same time, the original, primary and secondary follicles were observed and measured after the tissue section and HE staining of ovary, and the number changes of follicles at different stages were compared and analyzed. The results showed that the weight of ovary and fallopian tube showed an increasing trend with the development of laying period, and the number of four kinds of pre-hierarchical follicles reached the highest value at the peak egg-laying period. The number of the secondary follicles was the highest in the prelaying period, and the number of the secondary follicles with different diameters varied in the course of laying period. In addition, the average diameter of the primary follicle was also different at different laying periods.