Objective: This study aims to systematically evaluate the efficacy and safety of metformin combined with insulin therapy in managing type 1 diabetes mellitus (T1DM) in children. It particularly focuses on the impact of this combination therapy on physical fitness and game participation, providing an evidence-based reference for clinical treatment. Methods: A comprehensive search was conducted in databases including PubMed, Cochrane Library, Embase, Clinical Trials, CNKI, and Wanfang Data library, covering all publications up to May 2022. The selection criteria focused on randomized controlled trials examining the use of metformin and insulin in combination for treating children with T1DM. Data analysis was carried out using Revman5.40 software. Results: A total of 17 studies meeting the inclusion criteria were analyzed in this meta-analysis, encompassing 1119 children with T1DM. The analysis revealed no significant difference in blood glucose levels, body quality index, total adverse reaction events, or impact on physical fitness and game participation between the study and control groups. Notably, the study group exhibited significantly lower fasting blood glucose levels, 2-hour postprandial blood glucose levels, glycosylated hemoglobin levels, and daily insulin dosage, along with a shortened time to reach glycemic targets. However, the risk of gastrointestinal adverse reactions was notably higher in the study group. Conclusion: The combination of metformin and insulin in treating children with T1DM shows significant benefits in controlling blood glucose levels and reducing daily insulin requirements, potentially supporting better physical fitness and game participation. However, the increased risk of gastrointestinal adverse reactions warrants careful monitoring and management in clinical practice.