The treatment of medial collateral ligament injury can be conservative or surgical depending on the degree of injury. In conservative treatment, if the medial collateral ligament is only partially damaged and not completely ruptured through magnetic resonance examination, it can be treated by cast immobilization for one month and at the same time applying medicines for activating blood circulation and removing blood stasis, which is a good conservative treatment. Surgical treatment should be actively carried out to repair the medial collateral ligament if it is found to be completely ruptured by magnetic resonance examination. Most of the medial collateral ligament injuries have obvious trauma history, manifested as obvious pressure pain, swelling and subcutaneous bruise on the medial side of the knee joint after sprain or fall, and pain aggravation on the medial side of the knee joint during lateral knee joint pressure or lateral stress test in physical examination, which can be used as the basis for diagnosis.