Objective To evaluate the efficacy and safety of dapagliflozin in the treatment of diabetic kidney disease (DKD) in the real world. Methods A total of 84 DKD patients who received dapagliflozin in our hospital from Jan. 2018 to May 2020 and who were followed up for more than 12 months were selected. The effects of dapagliflozin on blood glucose, blood pressure, body weight, blood lipid, proteinuria and renal function of DKD patients were analyzed retrospectively, the differences of clinical outcomes before and after treatment were compared, and the adverse reactions during treatment were recorded. Results Of the 84 patients, the average age was (52.47±8.87) years and 56 cases (66.7%) were males. The diabetes history was 8 (3, 17) years, 35 cases (41.7%) had obesity and overweight, 47 cases (56.0%) had diabetic retinopathy, 69 cases (82.1%) had hypertension, the 24-h urinary protein level was 3 100 (700, 9 100) mg, and the estimated glomerular filtration rate (eGFR) was 87.1 (49.7, 108.2) mL/(min·1.73 m²). During the follow-up period, 12 cases (14.3%) stopped dapagliflozin (4 males and 8 females). Females were more prone to urinary tract infections (17.9%[5/28]vs 1.8%[1/56]; odds ratio[OR]=11.96, 95% confidence interval[CI]1.32-108.07, P=0.007). After 12 months of follow-up, body weight (P=0.02), body mass index (BMI) (P=0.02), systolic blood pressure (P=0.04), total daily insulin dosage (P<0.01), fasting blood glucose (P<0.01), the glycated hemoglobin (P<0.01), and 24-h urinary protein level (P=0.05) were significantly decreased. Conclusion Based on the real-world observational data, dapagliflozin is a relatively safe and effective drug for DKD.