Knee pain when standing up is common in the following diseases: first, patellofemoral arthropathy, the patient manifests as joint pain when going up and down stairs and squatting, the symptoms can be relieved after rest, accompanied by a feeling of weakness in the knee joint and playing soft legs. The pain is usually obvious at the beginning of the movement, and after a period of time the pain decreases, after too much movement the symptoms reappear and even increase, in serious cases where the half squat force, emergency stop, emergency turn that pain, affecting participation in sports, the most serious cases can also appear walking pain, rest pain and sedentary pain, weather changes may also be related to pain. Secondly, meniscal injury, this disease can have knee extension pain and joint space pressure pain, meniscal injury ipsilateral joint space convexity, popping and crossed cords, positive McDonald’s sign and swing test, nuclear magnetic can show meniscal tear, if the signs and auxiliary examination are not typical, need to carefully examine the patellofemoral joint.