Objective: To investigate the therapeutic effects and pharmacological mechanisms of Yishen Xingyang capsule (YXC) in oligoasthenospermia (OA) rats.Methods: Forty-eight male Sprague-Dawley rats were randomly divided into eight groups of six rats each:normal control (NC);model control (MC);three different positive drug (PD);and low-, medium-, and high-dose YXC groups. A rat model of OA was established by administering glucosides of Triptery-gium wilfordii Hook. F (GTW). After YXC administration, penile erectile function was observed. The epididymis, blood, and testes of the rats were harvested for analysis of sperm quality, sex hormone levels, mitochondrial membrane potential, and the transforming growth factor (TGF)-β1/Smad signaling pathway. Results: Compared with that in the MC group, penile erectile function in the YXC groups and three PD groups increased (all P<.01). Moreover, sperm quality in the YXC groups and three PD groups improved (all P < .001). The levels of testosterone, follicle stimulating hormone, and luteinizing hormone in the three PD and YXC groups increased (all P<.05). The mitochondrial membrane potential in the three PD and YXC groups significantly improved (all P<.001). Furthermore, the YXC and three PD groups showed decreased TGF-β1 expression (all P< .05) compared with the MC group. The high-dose YXC group and three PD groups improved Smad2 and Smad4 expression (all P<.05). Conclusion: YXC improved penile erectile function and sperm quality in OA rats, and the underlying mechanism included increase in sex hormones, inhibition of sperm apoptosis, and regulation of the TGF-β1/Smad signaling pathway. Meanwhile, this study provides a new effective drug option for the treat-ment of OA, which is beneficial to male reproductive health and social harmony.