Objective：To detect whether Panax notoginseng saponins（PNS） could improve the erectile function of diabetic mellitus （DM） rats with erectile dysfunction（ED），to find the possible ways by which PNS worked and to explone effects of PNS on Bax and Bcl-2 expressions. Methods：Model of DMED was established and the rats were randomly divided into four groups：PNS treated group（intraperitoneal injection with doses of 50 mg/（kg·d），100 mg/（kg·d），150 mg/（kg·d）） and DMED group（intraperitoneal in－jection with saline）；at the same time，normal rats injected with saline were taken as controls（normal control group）. Four weeks later，ratio of intracavernous pressure（ICP） and mean arterial blood pressure（MAP） was measured by electro-stimulating of cavernous nerve. Then cavernous bodies of penis of all experimental rats were harvested and their expressions of Bcl-2 and Bax were determined by immunohistochemistry. Apoptosis of penile tissue cell was detected by TUNEL. Changes of the cavernous bodies in ultrastructures were observed by electron microscopy. Results：ICP/MAP was elevated and value of Bcl-2/Bax was increased in middle and high dose group than in DMED group. Results of electron microscopy uncovered that there were ruptured endothelium and impaired smooth muscle cells in the low dose PNS group and DMED group and even thrombosis in DMED group；in the middle，high dose group and normal control group，there were no abnormal changes. Conclusions：PNS might elevate the value of Bcl-2/Bax to protect endothelium and smooth muscle cells from apoptosis as well as protect the function of penis cells，thereby to improve erectile function.