BACKGROUND: Knee joint stiffness is a common post-traumatic dysfunction, which is an urgent problem to be solved. To establish an ideal animal model of knee joint stiffness is the basis for studying the pathological mechanism of knee joint stiffness and is also important for exploring the treatment of knee joint stiffness. OBJECTIVE: To review the methods of establishing animal models of knee joint stiffness and to summarize the selection of animals, different fixation methods, fixation time and successful cycle, thereby providing experimental basis for its related research. METHODS: The literatures published from 2000 to 2020 were searched in the databases of CNKI, VIP, WanFang, PubMed, and Embase with the keywords of “knee stiffness, knee contracture, animal model” in Chinese and “knee stiffness, stiff knee, stiff knee, animal model” in English. Finally 49 references were included for review. RESULTS AND CONCLUSION: At present, researchers mainly use surgical methods and non-surgical methods for modeling, that is, surgical methods: through surgery with or without knee articular surface injury, internal fixation is used to cause postoperative traumatic joint stiffness; non-surgical methods: simple external fixation or violent injury external fixation is used to obtain the animal model of knee joint stiffness. In clinical practice, knee joint stiffness caused by immobilization after lower limb fracture is very common. For knee joint stiffness caused by lower limb fracture that does not affect the knee joint surface, the surgical fixation of extra-articular injury can be selected for modeling. For knee joint stiffness caused by knee joint articular surface injury, intra-articular injury fixation can be selected for modeling. The method of surgical fixation has the advantages of short modeling time, high efficiency, and good stability, but there are high requirements for aseptic conditions. To date, it has been widely used in the structural changes and efficacy observation of knee joint stiffness, and orthopedic brace intervention. The model of simple external fixation such as plaster and splint is easy to operate, avoids surgical trauma, and has relative advantages in simulating the disease development of knee joint stiffness. This model can be used to observe the pathological changes of joint stiffness at different stages, and the disadvantages are that the fixation is easy to loosen, slip, or nibble during the process of animal activities, the modeling time is too long, and the fixation is easy to fail. Fixation after violent injury can simulate knee joint stiffness caused by immobilization after periarticular soft tissue injury and is suitable for the study on the efficacy and screening of conservative treatment. In summary, the most ideal way to model knee joint stiffness is knee hyperextension+intra-articular surgical trauma+fixation. Through knee hyperextension to damage the posterior capsule of the knee joint and fenestration in the femoral condyle to simulate intra-articular fractures, this modeling method using Kirschner wire internal fixation has a short modeling time, high success rate, and good stability. [ABSTRACT FROM AUTHOR]