Objective:To observe the clinical efficacy of Qizhen Ziyin Mixture in the treatment of late onset hypogonadism with syndrome of kidney-yin deficiency. Methods152 patients of late onset hypogonadism with syndrome of kidney-yin deficiency were randomly divided into the treatment group and control group,76 cases in each group. The treatment group was treated with Qizhen Ziyin Mixture,and the control group was treated with testosterone undecanoate,with a course of 8 weeks. The changes of TCM syndrome scores,symptomatic inventory for screening late onset hypogonadism(SILOH) scores, the serum level of total testosterone(TT)and body mass index(BMI)were observed.  Results:①For the comparison of treatment before and after,the differences on the scores of soreness and weakness of waist and knees,spiritlessness and weakness,tidal fever and night sweating,insomnia and amnesia,asexuality and erectile dysfunction in both groups were statistically significant(P<0.05).For the comparison after treatment,the score of tidal fever and night sweating in the treatment group was lower than that in the control group(P<0.05),the score of erectile dysfunction in the control group was lower than that in the treatment group(P<0.05),and there were no statistically significant differences on the other scores between the two groups(P>0.05). ②For the comparison of treatment before and after,the differences on the SILOH scores of physical fitness,vasodilation and vasoconstriction symptoms,mental and psychological symptoms and sexual function symptoms in both groups were statistically significant(P<0.05). For the comparison after treatment,there was statistically significant difference on the score of sexual function symptoms between the two groups(P<0.05),and the differences on the other scores were not statistically significant between the two groups(P>0.05). ③For the comparison of treatment before and after,the difference on the testosterone level in both groups was statistically significant(P<0.05),the significant change of BMI was not found in both groups(P>0.05). For the comparison after treatment,there was statistically significant difference on the testosterone level between the two groups(P<0.05),and the differences on BMI was not statistically significant between the two groups(P>0.05).  Conclusion:Qizhen Ziyin Mixture can improve the clinical symptoms in patients of late onset hypogonadism with syndrome of kidney-yin deficiency,which shows similar effects as hormone alternative therapy.