This is a multicentre, randomized, open-label, parallel group, diabetic diet controlled study. 240 patients who meet Inclusion/Exclusion criteria will be randomized into test groups or control groups at the ratio of 1:1. Test group will use low protein diet in combination with compound α-Keto Acid tablet, while control group will use routine diabetic diet, efficacy and safety of test group will be compared with those of control group after 1 year treatment. The study will be performed at 12 centres to ensure that at least 200 evaluable subjects are obtained.