Objective: To determine the changes in serum bone metabolism indexes and ultrasonic bone mineral density (BMD) in patients with diabetic nephropathy at different stages, and their effects on diabetic renal microvascular complications. Methods: This is a clinical comparative study. One hundred twenty two diabetic patients admitted to the Baoding No.1 Central Hospital from January 2020 to March 2022 were selected as subjects and divided into three groups according to their actual condition: the simple diabetes (Group-A, 40 cases), diabetic nephropathy with micro urinary protein (Group-B, 40 cases) and diabetic nephropathy with massive proteinuria (Group-C, 42 cases). Another 36 healthy subjects were selected as the control group. Differences in serum bone metabolism indexes and ultrasound BMD levels were compared. Results: Twenty five hydroxy-vitamin D, BGP, T-PINP and ultrasound BMD levels in the control group were > Group-A> Group-B> Group-C, PTH and B-CTX in the control group were < Group-A< Group-B< Group-C, statistically significant differences (p<0.05). The urinary albumin to urinary creatinine ratio (ACR) value in Group-B was significantly lower than Group-C (p<0.05). Logistic regression analysis showed that 25-hydroxy-vitamin D, PTH, BGP, B-CTX, T-PINP and ultrasound BMD were the influencing factors of diabetic renal microvascular complications (p<0.05). Conclusion: Bone metabolism indexes and ultrasound bone mineral density are abnormally expressed in patients with diabetic nephropathy at different stages, which are closely related to the urine protein of patients. They have important clinical value in the diagnosis of early diabetic nephropathy.