Studying heart rate variability by 24 hours ECG holter of 139 patients with diabetic nephropathy compared to those of 108 type 2 diabetic meliitus without kidney injury and 30 healthy people, the results show that average heart rate variability index of patients with kiney injury is significantly decreased compared to that of patients without kidney injury or healthy people group, p 0.01. Ratio of patients who has low heart rate variability index (compered to healthy people group) of type 2 diabetic millitus with kidney injury higher significantly compared to that of patients without kidney injury, p 0.05 and 0.001. The positive mild corelations between heart rate variability index and glomerular filtration rate is detected, p 0.05.