Common causes of leg pain and swelling include vascular diseases of the lower limbs, local infections, lower limb tissue injuries, rheumatic immune diseases, gout, etc., which require timely consultation to find out the causes. 1. Lower extremity vascular diseases: including deep vein thrombosis, lower extremity arterial occlusion, etc., due to the obstacle of blood circulation, which will cause limb ischemia and hypoxia, resulting in swollen feet and foot pain. 2. Local infections: more common are dengue, metatarsal bone bacterial infection, etc., due to inflammation will lead to local redness, swelling, heat and pain. 3. Lower limb tissue injury: when the leg is injured by indirect or direct violence, it will lead to tissue congestion and edema, and in serious cases, it will lead to fracture and joint dislocation, which is also an important cause of swelling and pain. 4. Rheumatic immune diseases: rheumatoid arthritis is common, which can lead to synovial membrane lesions, and can also cause swelling and pain in the legs. 5. Gout: abnormal purine metabolism in the body, resulting in excessive production of uric acid, will produce non-specific inflammation in the synovial membrane of the joints of the lower limbs, which can cause pain and swelling of the legs. Diseases that can cause leg pain and swelling also include leg tumors, fracture non-healing and other diseases, if through rest and other self-conditioning can not be improved, it should be taken seriously, go to the regular hospital in a timely manner to find out the cause of the disease, and comply with the doctor’s instructions to standardize the treatment, to avoid delaying the condition.