Abstract: Objective:To investigate the effects of oyster oligopeptides(OOP)at different doses on sexual and reproductive functions in male partial androgen deficiency syndrome(PADAM)rats. Methods:Male SD rats were randomly divided into five groups:Normal control group(NC group),PADAM control group(PC),PADAM+low,medium and high dose OOP group(PLO,PMO,PHO). In addition to NC group,the other rats were supplemented with OOP at different doses while PADAM was induced by cyclophosphamide(CTX). Serum testosterone(TT),free testosterone(FT),luteinizing hormone(LH),follicle stimulating hormone(FSH)and testicular androgen receptor(AR),capture latency,mating latency and number of catches and mating,sperm quantity,viability and vitality in epididymis were measured 6 weeks later. Results:Compared with NC group,the contents of serum TT,FT,LH,the mating times and the number,viability and vitality of sperm in PC group significantly decreased(P<0.05),the capture latency and mating latency significantly increased(P<0.05). Compared with PC group,the capture latency was significantly shortened(P<0.01),and the times of capture and mating in PLO group were significantly increased(P<0.01). Except for no significant increase of sperm number in PMO group(P>0.05),the contents of serum TT,FT,FSH,LH,testicular AR and the times of capture and mating,the sperm number,viability and motility in the PMO and PHO groups increased significantly(P<0.05),the latency of capture and mating was significantly shortened(P<0.05). And the serum TT,FSH contents and mating times in PMO and PHO groups as well as the contents of serum LH and testicular AR in PHO group were significantly higher than those in PLO group(P<0.05). Conclusion:Oral oyster oligopeptides can effectively prevent the formation of PADAM induced by CTX through improving HPG axis,significantly improve sexual and reproductive functions,and has a certain dose effect,with the best effect of medium and high dose.