Abstract: Radiotherapy is the first treatment choice for nasopharyngeal carcinoma. With the rapid development of image-guided radiotherapy, adaptive radiotherapy (ART) has become widely available in clinical practice. ART may be implemented to monitor the anatomical or physiological variations of patients using dynamic imaging technology and feedback information during the treatment course, including geometric changes (size, shape, and position) of tumor and normal organs. ART also allows the modification of the treatment plan to accurately deliver the maximize dose to target and minimize normal tissue explosion. This review discusses the physics basis of ART and its state-of-art application and potential pitfalls.