The change of joint line height after Total Knee Arthroplasty (TKA) may lead to the limitation of flexion and extension after operation. Excessive upward movement of joint line can lead to the impact of tibial plateau or spacer on the lower edge of patella during knee flexion, which affects the knee extension device, increases the stress of patellofemoral joint, causes flexion limitation and patellar pain. It even causes failure of the extensor mechanism. At present, most of the studies on the change of joint line height are theoretical, and the clinical research is relatively small. This article reviews the domestic and foreign literature in recent years through the databases of CNKI, Pubmed and SCI, and reviews the measurement of joint line height, biomechanical research, influence on clinical function and prevention strategies. To provide theoretical reference for clinical surgeons, so as to improve the clinical function of patients and improve patient satisfaction.