Abstract: Objective To investigate the efficacy and mechanism of alendronate sodium combined with insulin in the treatment of osteoporosis(OP) in the patients with type 2 diabetes mellitus(DM). Methods Total 94 cases of OP among patients with T2DM in our hospital between March,2015 and March,2016 were enrolled and randomly divided into observation group(47 cases) and control group(47 cases).On the basis of routine treatment,the control group was administrated with metformin and insulin,while the observation group with alendronate sodium and insulin.The levels of serum glycosylated hemoglobin(HbA1c),fasting blood-glucose(FBG),serum calcium(Ca),tartrate-resistant acid phosphatase 5b(TRAP-5b),bone gla protein(BGP),and bone-specific alkaline phosphatase(BAP) were tested.The bone mineral density(BMD) of the femoral neck,Wards triangle and greater trochanter were measured by DPX-LBMD dual energy x-ray measuring instrument. Results The total effective rate was 89.36% in the observation group and significantly higher than that(72.34%) in the control group(P<0.05).The levels of BAP,TRAP-5b and BGP after the treatment in the observation group were improved more significantly as compared with the control group(all P<0.05).The BMD of the femoral neck,wards triangle and the greater trochanter in the observation group were significantly higher than those in the control group(all P<0.05). Conclusion Alendronate sodium combined with insulin in the treatment of osteoporosis among the patients with type 2 diabetes mellitus can effectively improve the level of bone mineral density,with remarkable effect,high safety,and is worthy of promotion.