Standing for a long time knee pain can be caused by the following reasons: First, osteoarthritis of the knee joint, severe osteoarthritis of the knee joint can lead to secondary cartilage damage, resulting in the narrowing of the medial and lateral gaps of the knee joint, resulting in increased pressure on the gaps after prolonged standing, resulting in symptoms of knee pain, which should be examined by X-ray and CT of the knee joint for diagnosis and early treatment. Second, damage to the meniscus of the knee, when there is a tear in the meniscus of the knee, or in adolescents with a discoid meniscus, the meniscus can be squeezed after prolonged standing and pain can occur, then the MRI of the meniscus should be examined for diagnosis and early treatment. Third, damage to the ligaments around the knee joint, when there is damage to the patellar ligament or the tendon of the quadriceps muscle of the knee joint, there can also be knee pain after standing for a long time, then it is necessary to check the MRI of the ligaments and blood tests for diagnosis and treatment.