Aim To evaluate the therapeutic effects of simvastatin,probucal,captopril and chinese medicine on endothelium function of atherosclerosis(As). Methods The rabbits of As were given simvastatin, probucal, captopril and chinese medicine respectively for 12 weeks. The blood were drawn for measuring the lipids,malondialdehyde, superoxide dismutase, nitric oxide and endothelin 1 (ET 1). The endothelium dependent vascular relaxation (EDVR) of abdominal aorta was examinaed by injecting acetylcholine (Ach). The mRNA expression of inducible nitric oxide synthease (iNOS), ET 1, angiotensin converting enzyme (ACE) of As were examined by reverse transcription polymerase chain reaction. Results The aortic contraction caused by Ach decreased in probucal, simvastatin, chinese medicine and captopril groups than regression control group. Both total cholesterol and intima medial thickness showed negative correlations with EDVR(r=-0.57,0.47 respectively). In normal group, mRNA of iNOS, ET 1 and ACE were expressed in low levels. In comparison with regression control group, mRNA expression of iNOS,ET 1 and ACE in 4 drug therapy groups decreased, iNOS in probucal and captopril groups and ACE in probucal, captopril and chinese medcine groups reduced. Conclusion The 4 drugs can improve the EDVR disfunction in atherosclerosis and probucol has the best effect. EDVR improvement may be associated with the mechanisms of reducing expression of iNOS, ET 1 and ACE genes, and reduction of lipid peroxide.