AIM:To investigate the injurious effects of oxidized low-density(OLDL) on human endothelial cells(ECs) and protective effects of Angelica Sinensis in vitro. METHODS: The effect of OLDL on nitric oxide (NO) release from EC and intercellular adhesion molecule-1 (ICAM-1) expression on EC surface were studied, and the protective effects of Angelica Sinensis on normal and abnormal EC were investigated using cultured EC with or without OLDL and immunocytochemical staining technique. RESULTS: OLDL led to a decrease of NO release and an increase of ICAM-1 expression, which can be reversed by Angelica Sinensis and atropine can block this role of Angelica Sinensis. CONCLUSION: Angelica Sinensis has antagonistic effect on OLDL-induced decreasing of NO released from ECs and increasing of ICAM-1 expression on ECs surface . These effects of Angelica Sinensis may be exerted by the excitation of muscarinic receptor.