Knee pain after walking for a long time may be a manifestation of osteoarthritis, joint effusion or joint ligament damage. 1. Osteoarthritis: Osteoarthritis is a relatively common chronic disease, often with degenerative changes in the joint tissues, joint activities will be limited to a certain extent, when walking for a longer period of time, there will be symptoms of knee pain. 2. Joint effusion: when there is acute or chronic injury to the joints, it may lead to increased exudation of joint fluid, joint effusion, increased pressure in the joint cavity, resulting in joint pain, and the pain may worsen after walking for a long time. 3. Joint ligament injury: the existence of joint ligament injury, has not yet fully recovered, will also appear after walking for a long time knee pain. There are many reasons for knee pain after walking for a long time, if it occurs every time you walk more, or the pain is not relieved after resting, it is recommended to consult a doctor to clarify the cause.