Objective To investigate the effect of solifenacin and epalrestat combination therapy on type 2 diabetes complicated with overactive bladder (OAB).Methods A total of 80 patients with T2DM and OAB were randomly divided into three groups:control group (Con group,n=24),epalrestat group (n=29),and solifenacin combines epalrestat group (n=27).Con group was treated with conventional therapy such as routine bladder training,anti-hyperglycemic,anti-hypertensive,lipid lowering treatment,and nerve nutrition.Epalrestat group was treated with epalrestat 50 mg,3/d orally on the basis of conventional treatment.Solifenacin group was treated with solifenacin 5 mg,1/d,and epalrestat 50 mg,3/d orally.All the subjects were followed up for 12 weeks.Voiding diary,OAB self rating scale (OABSS) score,maximum urinary flow rate (Qmax),average urinary flow rate (Qave),and urine volume(VV) were recorded.Results The daily micturition frequency in 24h,times of nocturia,urgency,frequency,and urinary incontinence,and OABSS scores were lower,while Qmax,Qave,and VV were higher in solifenacin group than in Con group and epalrestat group (P<0.05).The OABSS scores were lower while VV was higher in epalrestat group than in Con group (P<0.05).The total effective rate was higher in solifenacin group than in Con group and epalrestat group (92.6% vs 69% vs 41.7%,P<0.05).Conclusion Solifenacin and epalrestat combination therapy was effective in treating patients with T2DM and OAB.