High flexion squat is extremely common in the daily activities of Asian countries and certain occupations. In this paper, different types of deep squats and their motion characteristics were summarized, and recent research progress of squat biomechanics was reviewed. Different research methods on squats such as in vitro experiment, in vivo test and computer simulation were also classified and represented. Biomechanical studies on deep squat of the knee can benefit establishment of reasonable rehabilitation training, prevention of sports risks as well as provide some references for optimization of knee prosthesis design.