Abstract: OBJECTIVE To explore the mechanism of intervention with atherosclerosis (AS) by Qingre Huoxue Yangyin Decoction and its functional units. METHODS The AS model of SD rats was successfully established with high fat diet and balloon injury.The model rats were randomly divided into model group， whole group， Huoxue group， Yangyin group， Qingre group and positive group， and received the intragastric administration， respectively.The blank group was fed with normal diet without medication.The changes of each group on blood lipid， arterial lesion and Th1/Th2-related cytokines were observed after 4 weeks. RESULTS ①Compared to the model group， the whole decoction significantly reduced the plaque proportion and TG(P<0.05)， increased HDL-C(P<0.05) ; reduced Th1-related cytokines TNF-α and INF-γ(P<0.05)， increased Th2-related cytokine IL-4(P<0.05).②Each function unit compared with the model group: Yangyin group obviously elevated IL-4 and decreased TG (P<0.05)， Qingre group obviously decreased the IFN-γ， LDL-C and plaque proportion (P<0.05)，Huoxue group significantly reduced plaque ratio（P<0.01）. CONCLUSION Qingre Yangyin Huoxue Decoction and each function unit can play a role in anti-atherogenesis by lowering blood lipids and regulating Th1 and Th2 subpopulations differentiation imbalance.