OBJECTIVE： To evaluate the improvement effects of sitagliptin on islet B-cell function in type 2 diabetic patients systematically， and to provide evidenced-based reference. METHODS： Retrieved from PubMed， Cochrane library， EMBase， CJFD， Wanfang database， VIP and CBM， RCTs about sitagliptin alone or combined with routine plan （trial group） vs. placbo alone or combined with routine plan （control group） in the treatment of type 2 diabetes were collected. Two reviewers independently screened studies according to exclusion and inclusion criteria， extracted data， and assessed the methodological quality according to Cochrane Manual 5.1.0. Meta-analysis was performed by using RevMan 5.3 software. RESULTS： A total of 5 RCTs were included， involving 1 253 patients. The result of Meta-analysis showed that changes of islet B cell function index （Homa-B） [sitagliptin alone group： MD＝9.21，95％CI（4.16， 14.25），P＜0.001； drug combination group： MD＝7.24，95％CI（0.80， 13.68），P＝0.03] and changes of insulin resistance index （Homa-IR） [sitagliptin alone group： MD＝－0.40，95％CI（－0.44，－0.36），P＜0.001； drug combination group： MD＝－0.35，95％CI（－0.63，－0.07），P＝0.02] of trial group were significantly better than those of control group， with statistical significance. CONCLUSIONS： Sitagliptin shows certain therapeutic efficacy in improving islet B cell function and insulin resistance.