Objective　 To investigate the effect of Emodin on the secretion of MCP-1 in peripheral blood mononuclear cells (PBMCs) of patients with diabetic nephropathy. Methods Thirty-two patients of diabetic nephropathy treated with insulin and 24 healthy control were studied. PBMCs were isolated by density gradient centrifugation with Ficoll-Paque and divided into four groups. The effect of Emodin with different density(0、10、50 and 100(g/ml) on MCP-1 secretion in peripheral blood mononuclear cells of patients with diabetic nephropathy which was examined by ELISA were observed. Results The level of MCP-1 in peripheral blood mononuclear cells of diabetic nephropathy patients were higher than that of the normal controls （78.4±35.67 vs 29.3±17.31pg/ml, P<0.05）, which were positively related to the level of urinary albumin and the serum creatinine respectively (r=0.633，P<0.05；r=0.701， P<0.05）. MCP-1 level of patients with diabetic nephropaty decreased obviously by Emodian and the decreasing degree were enhanced by the increasing of Emodin density. Conclusion Patients with diabetic nephropaty have higher MCP-1 level compared with normal controls.Emodin could downregulate the express ion of MCP-1, which probably constituted the important parts of the mechanism of Emodin functon as of decreasing urinary protein and improving renal function.