Abstract： Objective To investigate the therapeutic effects of Tongxinluo and its influence on the expression of CD40 and CD40L in artherosclerosis rabbits. Methods 60 male rabbits were divided into three groups randomly,20 of each group: normal control group, model group and Tongxinluo group. The rabbits in model group and Tongxinluogroup were used to prepare the atherosclerosis model induced by high-cholesterol diet. The levels of ET-1, NOwere measurde. Before and 12 weeks after durg treatment,serum total cholesterol ,plaque areas and ratios of intima/media thickness were detected. The expression of CD40 and CD40L mRNA were determinated by quantitive RT-PCR. Results Serum total cholesterol level of Tongxinluo group was decreased compared with model group ( P < 0. 05 ), and they were both much higher than those of normal control group ( P < 0. 01 ); as compared with the model group, aortic plaque areas and ratios of intima/media thickness in Tongxinluo group reduced significantly [ (0.56 ± 0. 07) vs ( 1.16±0.08),P<0.01;(36.88±2.38)% vs (76.58 ±2.86) %,P <0. 0l] ;The expression of CD40 and CD40L mRNA also decreased in Tongxinluo group with statistic significance[ (0.798 ± 0.115 )、 (0. 592 ± 0. 132) vs (0.686±0. 132) 、(0.498 ±0. 108) ,P <0. 01 ) ]. Conclusion Tongxinluo had the ability to anti-artherosclerosis and its possible mechanism was down-regulate the expression of CD40 and CD40L.