Objective:Analysis and comparison on FSH in early follicular phase or in dominant follicular phase of treatment of small follicle ovulation.Methods:62 cases with small follicle ovulation were randomly divided into two groups,Group A 50 cycles,with FSH in early follicular phase;Group B 52 cycles,with FSH when the follicle was dominant follicle;Then,The pregnancy rate and early abortion rate and etc of Two groups were studied.Results:The pregnancy rate and early abortion rate of Group B and group A has no statistical significance.Conclusions:Ovulation with FSH when the follicle was dominant follicle is safe and effective.