Abstract： Objective To evaluate the efleet of continuous subcutaneous insulin infusion (CSII)combined with mefformin hydroehloride( Met H)on type 2 diabetic patients. Methods 240 patients with type 2 diabetes melli-tus (T2DM) were divided into 3 groups randomly: CSII combined with Met H ( A group: n=80) ; simple CSII ( B group:n=80) ; multiple deliver insulin (MDI) ( C group: n=80). The levels of blood glucose, HbA1 e, therapeutic time, a-mount of insulin, Fins ,C-P, HOMA-IR and IAI were compared among them before and after 10d of treatment. Results GroupA, B eornpared with group C, the levels of HbA1 e significantly deeroased in other two groups [ ( 8.0±3.2)%vs. (6.9±1.4)% and(7.0±1.2)% ] (aU P<0.05),so did the therapeutic time[(6.0±1.9)d vs. (3.0±1.4) and(3.5±1.5) d] and insulin dose[ (55.0±17.0) U/d vs. (38.0±15.0) U/d and(45.0±16) U/d] (all P<0.05). The insulin dose was much less in group A than in group B. Versus group B and C,the HOMA-IR of group A (0.8±0.3 vs. 1.5±0.4 and 1.6±0.4)decreased(P<0.05) ,and IAI(-2.0±4.3 vs. -3.6±4. 2 and -4.1±4.3) increased (all P<0.05), without the function impairments of heart, liver or kidney. Conclusion CSII in combi-nation with mefformin hydreehloride can significantly enhance the treatment effect of the patients with type 2 diabetes mellitns; reduce blood glucose and HbA1 e, improve insulin resistenee,lessen insulin need.