The smooth muscle cell-derived foam cell formation is one of the characteristics at the intermediate and late stages of atherosclerosis, In this paper we studied the effect of macrophages on the formation of smooth muscle cell-derived foam cells,The volumes of oxidized low density lipoprotein binding and uptake were measured with cell enzyme linked immunosorbent assay method to show the scavenger receptor activities,The contents of intracellular cholesterol were also measured.The results indicat ed that macrophage conditioned medium could induce the smooth muscle cells ( SMC ) scavenger receptor expression and its intracellular cholesterol accumulation,and that increase the SMC intracellular cholesterol contents, This supported that macrophages could release some factors to enhance the SMC scavenger receptor expression and the intracellular lipid accumulation, and that the interaction between SMC and macrophages may play an important role in the development of atherosclerosis.