A method for preventing and/or treating diabetic nephropathies by means of plasminogen. Compared to other existing drugs for treating diabetic nephropathies, plasminogen has significant effects in improving a microvascular injury of kidney, reducing the thickening of the glomerular basement membrane and the glomerular mesangium, and the like.本發明涉及纖溶酶原預防和/或治療糖尿病腎病方面的作用。與現有其它糖尿病腎病治療藥物相比,本發明纖溶酶原具有顯著的改善腎臟微血管損傷,減少腎小球基底膜和腎小球系膜增厚等作用。