Background: This study aimed to evaluate the efficacy of transurethral thulium laser en bloc resection of the bladder tumor (TmLRBT) in patients with non-muscle invasive bladder cancer (NMIBC) and to investigate whether a second resection can be avoided.Methods: From June 2012 to June 2018, 251 newly diagnosed patients with NMIBC were enrolled in this retrospective study; all patients received regular administration of pirarubicin after the initial resection. A second transurethral resection (TUR) was performed in patients within 2–6 weeks after the initial TmLRBT in group 1. Patients in group 2 only underwent cystoscopy at 3 months.Results: Second surgery results indicate that recurrence was detected histopathologically in 6/108 and 11/143 patients in group 1 and 2, respectively (P = 0.52); Progression was observed in 2 patients in each group (P = 0.34). The mean follow-up duration was 40.1 months, with no significant difference between the groups (P = 0.32). Recurrence was observed in 23 (21.3%) and 39 (27.3%) patients in groups 1 and 2 during the follow-up, respectively (P = 0.34); disease progression occurred in 4 (3.8%) patients in group 1 compared with 7 (4.0%) in group 2 (P = 0.20).Conclusion: Complete removal of tumors can be achieved by TmLRBT. This technique may decrease the number of second TURs.