Diabetic nephropathy with heavy proteinuria have high risks of progressing to end stage renal disease. Though recent studies have shown that ACEI or ARB could reduce proteinuria of DN and slowed the progression to ESRD. But ARBs can only reduce proteinuria about 30%, so some patients still have heavy proteinuria,and then loss their renal function rapidly. So, to reduce the proteinuria of DN is a very important therapy target.