Aim The purpose of the study is to well understand expression of cyclin D in smooth muscle cells and its association with lipid peroxidation injury to endothelial cellls.Methods The lipid peroxidation injury to cultured endothelial cells was induced by diamide,then diamide stimulating endothelial cell-derived conditioned media were collected. After a 24-hour culture of smooth muscle cells exposed to various epithelial cell derived conditioned media, smooth muscle cells were collected, and used to immunocytochemistry stainning and proliferative test.Results Rabbit smooth muscle cells could express cyclin D, the reactant of immune reaction was mainly located in nuclei. The media conditioned by diamide stimulating endothelial cells induced stronger expression of cyclin D in smooth muscle cells (p<0. 01).Meanwhile the amount of 3H-TdR incorporation into DNA in smooth muscle cells induced by the media was obvious larger than that induced by normal endothelial cell derived conditioned media (p<0. 01).Conclusion The proliferation of smooth muscle cells is related to expression of cyclin D, lipid Peroxidation injury to endothelial cell may induce proliferation of smooth muscle cells through enhancing expression of cyclin D.