Objective The change of nitrogen oxide (NO) and gonadotropic releasing hormone (GnRH) in serum and cyclic guanosine monophosphate (cGMP) in bladder of emasculated female rat after treatment by Niaochangshu capsule was studied to investigate the mechanism of action of Niaochangshu capsule. Methods A total of 48 adult Sprague-Dawley female rats were randomly divided into normal group, model group, control group with Nilestriol and trial group with Niaochangshu capsule. Resect the ovaries to make the estrogen-lack model. After 4 weeks intragastric administration, the serum NO and GnRH and bladder cGMP of all rats were examined. Results The content of serum NO and bladder cGMP were significant lower in the model group than the other three groups (P 0.05). Conclusions In emasculated female rats, the content of serum NO and bladder cGMP can be significantly increased by the Niaochangshu capsule, and it is better than Nilestrio.