Objective To analyze the clinical characteristics of diabetes mellitus complicated by systemic lupus erythematosus (SLE) in children, and to explore the independent risk factors of diabetes mellitus complicated by SLE. Methods Children with SLE complicated with diabetes mellitus hospitalized in the Department of Nephrology from January 2016 to June 2022 were selected as the diabetes mellitus group, and children with SLE not complicated with diabetes mellitus hospitalized during the same period were selected as the control group, and the clinical data of the 2 groups were collected to analyze the risk factors of SLE complicated with diabetes mellitus. Results Fifteen children (7.4%) with SLE complicated with diabetes were included, 5 males and 10 females. The median age at onset of diabetes was 12.0 (11.0~13.0) years, the median duration of SLE at the time of diabetes was 25.5 (11.5~92.5) days, and the median fasting blood glucose was 11.3 (10.8~13.2) mmol/L. There were 6 cases with family history of diabetes. At the time of diabetes mellitus 10 children were on adequate hormone (prednisone acetate 2 mg·kg^-1·d^-1, maximum amount ≤60 mg/d) use. The control group included 151 children with SLE (42 males and 109 females). Compared with the control group, the diabetic group was older, had higher systolic and diastolic blood pressure, higher cholesterol and uric acid levels, and lower HDL levels; the proportion of children with abnormally high systolic blood pressure, abnormally high cholesterol and uric acid, abnormally low HDL, and a family history of SLE was higher; and the time for urinary protein to turn negative was longer, and the differences were all statistically significant (P<0.05). Multifactorial logistic regression analysis revealed that age, family history of diabetes mellitus, elevated levels of uric acid and cholesterol, and lowered levels of HDL were independent risk factors for diabetes mellitus complicating SLE (P<0.05). Conclusion If children with SLE are older, have a family history of diabetes mellitus with high levels of cholesterol, low levels of HDL and hyperuricemia, the occurrence of secondary diabetes should be alerted.