Medial collateral ligament injury is the most common injury of the knee ligament. Most patients with conservative treatment can achieve preinjury activity level. Nonetheless,it's necessary to eval-uate the severity of the injury and judge the best time and details for surgery as serious injury of the medial collateral ligament will cause chronic knee stability and accelerate its degeneration. This paper summarizes the current status of diagnosis and treatment for medial collateral ligament injury of the knee,aiming to pro-vide guidance for dealing with this lesion.