Non-muscle-invasive bladder cancer (NMIBC) accounts for approximately 75% of newly diagnosed bladder cancers and is characterized by a high risk of recurrence and progression. Current guidelines recommend that patients with stage T1 NMIBC undergo a second transurethral resection of bladder tumor (re-TURBT) within 2-6 weeks after the initial surgery to remove residual tumor, confirm staging, and obtain additional pathological information. However, the benefits of routine re-TURBT for all high-risk patients remain controversial, as many patients may not have residual disease, while the procedure carries surgical and anesthetic risks, physical and psychological burden, and additional healthcare costs. Urine tumor DNA (utDNA) refers to DNA fragments shed by tumor cells into urine. It can be detected using molecular assays with high sensitivity and specificity, offering a non-invasive method for bladder cancer diagnosis and surveillance. Previous studies have shown that positive utDNA results after initial TURBT may be associated with residual disease and higher recurrence risk. This multicenter, randomized controlled trial aims to evaluate whether utDNA testing can accurately identify NMIBC patients who are most likely to benefit from re-TURBT, thereby guiding the decision to perform the procedure. The goal is to optimize patient selection for re-TURBT, reduce unnecessary surgeries, and improve patient quality of life while maintaining oncologic safety.