The rotator cuff tear is a common clinical disease, and some patients can be asymptomatic. Ultrasound has a high diagnostic accuracy for the rotator cuff tendon tear. It can be used to assess the type, size, prognosis, etc. of tear before surgery, postoperative evaluation of the integrity and complications of the repair, as well as the unique advantages of new ultrasound technology in diagnosis and treatment, make the application of ultrasound in clinical work more and more extensive. Therefore, this article reviews the advances in ultrasound in the diagnosis of rotator cuff tears, before and after tear repair surgery, and the advances in new ultrasound techniques.