Bladder cancer is the most common malignant tumor in the urinary system. The standard treatment of muscle-invasive bladder cancer (MIBC) is the radical cystectomy combined with pelvic lymphadenectomy. In recent years, radiotherapy has played an important role in the MIBC bladder-preserving treatment model. This article will review the advances in the application of radiotherapy for bladder preservation in MIBC, and introduce the application progress of radiotherapy in trimodality therapy of adjuvant radiotherapy and chemotherapy after transurethral resection of bladder tumors, radical radiotherapy, preoperative radiotherapy, radiotherapy combined with immunotherapy, the development and challenges of radiotherapy technology, and radiotherapy-related adverse reactions. The aim of this article is to provide a reference for further exploration of a more scientific and effective comprehensive treatment mode for bladder preservation.