Objective: To study the inhibitory effect of chuanxiongzine on vascular smooth muscle cell (VSMC) proliferation and explore its molecular biology basis. Methods: we selected the VSMC cultured 4～8 generation from rat aorta thoracalis as research object.The objects were divided into four groups( Ⅰ )control group, ( Ⅱ )chuanxiongzine(50 μg/ml)group, ( Ⅲ )chuanxiongzine (100 μg/ml) group and( Ⅳ ) chuanxiongzine (200 μg/ml) group. The inhib itory effect of chuanxiongzine on VSMC proliferation was investigated by cell counting, MTT and 3H-TdR incorporation assay. In order to illuminate the molecular biology mechanism of chuanxiongzine inhibiting VSMCs proliferation, the expression of proliferating cell nuclear antigen (PCNA) and C-myc were detected.Results: Chuanxiongzine could inhibit the proliferation of VSMC significantly in a dose- and time-dependent manner, compared with control group (P ＜ 0.05). The expression of PCNA and c-myc were inhibited obviously and correlated with the concentration of chuanxiongzine (P ＜ 0.05). Conclusion: Chuanxiongzine may play a considerable role in VSMC proliferation process. The inhibitory effect of chuanxiongzine in a dose- and time-dependent manner can be realized via down regulating the expression of PCNA and c-myc. In this study, The great theoretical fundament about Chinese medicine, which is used to treat atherosclerosis (AS), has been obtained.