Aim To investigate the relationship of platelet-derived growth factor(PDGF-A) and the pathogenesis of atherosclerosis(As),the expression of PDGF-A in atherosclerosis(As)plaque of arteriosclerosis obliterans(ASO)patient and normal arterial wall were studied. Methods The protein level and area of PDGF-A in As plaques and normal artery of human were studied by means of immunohistochemistry. Results The arterial wall of ASO patient wasn' t smooth,and there were very few normal endothelial cell but a lot of foam cell.In contrast,the normal arterial wall was very perfect,endothelial cell and smooth muscle cell stood on line. The data of immunohistochemistry showed that the expression of PDGF-A was augmented significantly in As plaque of ASO patient.In contrast,in normal arterial wall the expression of PDGF-A was very low(p<0.01). Conclusions The data suggests that the increased expression of PDGF-A in As plaques of ASO related to the pathogenesis of ASO.PDGF-A play very important roles in the formation and progression of atherosclerosis.