The purpose of this study is to determine the efficacy and molecular mechanism of the effect of schisandrin b (SCHB) on treating erectile dysfunction (ED) in a rat model with bilateral cavernous crushing nerve injury.,The ED rat model was established with bilateral cavernous nerve crushing, and then confirmed by apomorphine. Fifty healthy eight-week-old ED rats were randomly assigned into five group, including control group (sham surgery), bilateral cavernous nerve crushing injury group (BCNC), BCNC with low SCHB (100 mg/d), BCNC with medium SCHB (200 mg/d) and BCNC with high SCHB (400 mg/d). For the last three groups, SCHB was given for 2 months. Then, we examined intracavernosal pressure (ICP), cyclic nucleotides (cAMP, cGMP), endothelial nitric oxide synthase (eNOS) and neuronal NOS (nNOS) in all groups.,In the study of ICP, SCHB was able to improve ED in a dose-dependent manner. In addition, as compared to the BCNC group, the relative expression of eNOS and nNOS in medium and high concentration of SCHB-treated groups are higher than BCNC group. Moreover, all groups treated with SCHB showed a significant higher expression level of cAMP and cGMP.,These results suggested that SCHB were able to significantly improve the ED on rat model through the NO-cGMP and cAMP- protein kinase A (PKA) pathway.