This is a multicenter, randomized, placebo-controlled study to evaluate the effectiveness and safety of low-dose aspirin (50 mg/day) in renal and cardiac function protection in people with diabetic nephropathy.

Inclusion Criteria:

• 1.Voluntarily sign informed consent;2.Meet the diagnosis of diabetic nephropathy: In the case of identifying diabetes as the cause of kidney damage and excluding chronic kidney disease caused by other causes, at least one of the following is present:①. In the case of excluding interference factors, at least 2 UACR≥30mg/g or UAER≥30mg/24h (≥20ug/min) in 3 tests within 3~6 months. ②. eGFR<60ml/min/(1.73m2)-1 for more than 3 months. ③. Renal biopsy consistent with pathological changes of DKD;3.DKD staging is 3 and before，eGFR>30ml/min/(1.73m2)-1；

Exclusion Criteria:

• (1) History of cardiovascular or cerebrovascular events (defined by the patient's medical history and/or instrumental examination results); (2)Insufficient glycemic control (i.e., glycated hemoglobin ≥8%); (3) Uncontrolled blood pressure despite taking antihypertensive drugs (≥140/≥85mmHg); (4) Previous major bleeding (i.e., intracranial hemorrhage); (5) Previous gastrointestinal ulcers; (6) Clinical diagnosis of type 1 diabetes mellitus (diagnosis of diabetes mellitus and use of insulin before age 35);(7) Patients with CKDG4 or G5 (i.e., eGFR<30 mL/min/1.73 m2 or dialysis) ;(8) chronic active infection or; (9) evidence of malignancy within the past 5 years. Patients with tumour disease in situ who are successfully treated only by local resection can be included in the study (including non-melanoma skin cancer in situ); (10) Autoimmune diseases; (11) Persistent arrhythmias requiring anticoagulation therapy (i.e., atrial fibrillation). In this category, isolated ventricular/supraventricular presystoles; (12) Use of NSAIDs or other antiplatelet drugs in the past 30 days; (13) cirrhosis of any etiology; (14) use of anticoagulants; (15) Life expectancy less than 1 year; (16) Known aspirin allergy; (17) Known pregnancy; and (18) Severe mental illness.