Aim To investigate the effect of testosterone on endothelial cells in male rabbits atherosclerotic models. Methods Male cholesterol-fed rabbits were divided into four groups at random: placebo group (castrated rabbits treated with placebo), group with low level testosterone (castrated rabbits treated with testosterone 0.25 mg/kg·d), group with high level testosterone (castrated rabbits treated with testosterone 2.5 mg/kg·d), sham operation group. Three months later, the rabbits were sacrificed. Testosterone level, lipids, plasminogen activator inhibitor activity (PAI), nitric oxide (NO), endothelin (ET) and angiotensinⅡ (AngⅡ) concentration were tested. And the ratio of aortic plaque area to total intima area was examined. Results It showed that testosterone level of placebo group was lower than those of the other groups (2.56±0.28 μg/L vs 7.67±0.61 μg/L, 40.16±0.93 μg/L, 7.79±0.61 μg/L, p<0.01); NO content of placebo group was lower than those of the other groups (39.0±9.5 μmol/L vs 62.8±8.9 μmol/L, 56.7±10.3 μmol/L, 51.5±9.3 μmol/L, p<0.05 or p<0.01); PAI of placebo group was higher than that of group with low level testosterone (567.3±53.4 u/L vs 334.4±51.3 u/L, p<0.01); ET of placebo group was higher than that of group with low level testosterone (911.9±15.4 ng/L vs 846.1±43.0 ng/L, p<0.05); and AngⅡ of placebo group was higher than that of group with low level testosterone (687.2±36.5 ng/L vs 624.5±54.5 ng/L, p<0.05); the ratio of aortic plaque area to total intima area of placebo group was higher than others (46.4%±9.3% vs 20.6% ±5.3%, 22.7%±4.6%, 28.5%±13.8%, p<0.01). Conclusions Testosterone is a protective factor for endothelial cells, thus to alleviate atherosclerotic lesion for male rabbits fed with high-cholesterol stuff.