Objective:To observe the regulation effect of AT1 receptor on the reproductive system of male mice,and preliminarily explore the mechanism of improving the reproductive function of ♂AT1+/－mice by Wuzi Yanzong pills, a traditional Chinese medicine compound. MethodsTwenty 8-week-old C57BL/6 normal male mice and 40 AT1KO heterozygous male mice(♂AT1 +/－) were randomly divided into group A(normal male mice group), group B(♂AT1 +/－mice group),and group C(♂AT1+/－mice + Wuzi Yanzong pills group). The mice in group A and group B were given intragastric administration with 0.9% NaCl solution,and the mice in group C with Wuzi Yanzong pills at 5.8 g/kg, twice daily with 0.5 mL each time. The expression of AT1 in testis, hypothalamus and pituitary was determined by RT-PCR method. Pregnancy rate was measured before sampling,and sperm morphology was observed in each group. Plasma sex hormone levels, including gonadotropin releasing hormone (GnRH), follicle stimulating hormone (FSH), luteinizing hormone (LH) and testosterone (T),were measured by ELISA enzyme immunoassay.  Results:Compared with the normal group, only a small amount of AT1 was detected in testis,pituitary and hypothalamus tissues in both groups of B and C(P<0.01), indicating that the model was successful. None of the female mice in cages with mice from group B and C were pregnant, but the sperm morphology in group B and C was significantly abnormal as compared with that in the normal group (P<0.01). After the intervention of Wuzi Yanzong pills, the normal rate of sperm was significantly increased, and there was significant difference between group C and group B (P<0.05). The level of GnRH in group B was significantly higher than that in group A (P<0.01). After the intervention of Wuzi Yanzong pills, the levels of GnRH and FSH in group C were significantly higher than those in group B (P<0.05).The levels of GnRH, FSH and LH in group C at the 4th week were higher than those in the second week of the same group (P<0.05).  Conclusion:The knockout of AT1 gene can lead to infertility in male mice. Wuzi Yanzong pills may improve the reproductive function of male mice by increasing the level of sex hormones and the normal rate of spermatozoa in AT1+/- mice.