Purpose:To investigate the clinical results of intravesical instillation with MMC and BCG for the prevention of postoperative recurrence of bladder tumor.Methods:86 cases of patients with superficial bladder cancer were included in this study. All patients received intravesical instillation of 20 mg MMC or 60mg BCG in turn once a week postoperatively, and persisted for 12 weeks. Then intravesical instillation was performed every 3 months, persisted for 2 years.Results: All patients have been followed up for 2.4 to 8 years, with a average of 4.8 years. The recurrent rate was 8.1%.Conclusions:Intravesical instillation of MMC and BCG in turn are effective for reducing the postoperative recurrence rate of bladder tumor.