Knee pain after squatting may be a normal physiological reaction, but also may be related to meniscus injury, knee arthritis, ligament strain and other factors. 1. Physiological factors: when squatting, the pressure between the femoral cartilage and patellar cartilage and meniscus will increase, and prolonged squatting will also lead to blood circulation, which will lead to knee pain, which can be seen in physiological conditions. 2. Meniscus injury: if the patient caused meniscus injury due to long time incorrect sports posture, after squatting for a long time, it will also cause pain due to the increased pressure on the meniscus. 3. Knee arthritis: knee arthritis is mainly caused by degenerative changes in the patient’s knee, patients with this disease have inflammation of the knee stimulation, squatting is easy to stimulate and produce pain. 4. Ligament strain: knee pain after squatting for a long time may also be caused by a slight ligament strain after squatting for a long time. Patients should go to the hospital in time to identify the cause and receive appropriate treatment.