Abstract: Objective：To observate the effect of pioglitazone combined with metformin on polycysticovary syndrome(PCOS).Methods：One hundred and four cases with PCOS were randomly divided into treatment group(56 cases) and control group(48 cases).The treatment group was treated with metformin and pioglitazone,the control group were only treated with metformin for 3 months.All cases were induced ovulation with Letrozole and hCG and the data of follicle stimulating hormone(FSH),serum levels of testosterone(T),luteum-stimulating hormone(LH),fasting insulin(FINS),fasting blood-glucose(FPG),and the rate of ovulation and pregnancy were measured.Results：The levels of LH,FPG and T in treatment group were significantly higher than those of control group(P〈0.01) and the levels of FSH,FINS,Syndrome unruptured follicular syndrome and the rate of ovulation and pregnancy were not statistical significant(P〉0.05).Conclusions：Pioglitazone combined with metformin can improve the hormone secretion,and ovulation and pregnancy are uninfluenced.