Objective For the purpose of studing superovulation in C 57BL/6J mice. Method 5IU+5IU or 10IU+10IU PMSG and HCG were used to stimulate superovulation of C 57BL/6J mice. After PMSG given at 4:30 p.m. on the first day, HCG was injected on the third or fourth day (48 h or 72 h later). Ova were flushed out of the oviduct 16h after administration of HCG. The ova's amount of each group was compared. Result The superovulation in first group (5IU+5IU PMSG and HCG, 48 h) was best. The ova's amount of mice in 8-10 weeks by superovulation was more than that in 6-8 weeks. Conclusion In C 57BL/6J mice, the best dosage of hormone for superovulation is 5IU PMSG + 5IU HCG, and the best interval of time for the administration is 48h.