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 inhibitory 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.