Objective: To evaluate the safety and efficiency of transurethral low-power thulium laser en bloc resection of non muscle-invasive bladder tumor. Methods: total of 40 non muscle-invasive bladder tumor patients treated in our hospital from May 2017 to May 2019 were enrolled, including 25 male patients and 15 female patients with the average age of (64.15±10.35) years old. All the patients were treated with transurethral en bloc resection by using the VELA-thulium laser under low power of 15-20 W. Results: All the operations were finished successfully in one time under general anesthesia. The average time of operation was (25.54±7.13) min. No obturator nerve reflex, bladder perforation and massive bleeding was recorded intraoperatively. There was no severe urinary tract infection and blood loss postoperatively. The mean following-up time was (14.20±2.13) months. 3 cases(7.5%) had tumor recurrence. Conclusions: Transurethral low-power thulium laser en bloc resection is a safe and effective therapeutic method in treatment of non muscle-invasive bladder tumor.