Weakness of legs and feet in elderly people over 80 years old may be caused by orthopedic diseases, cerebrovascular diseases or lower limb vascular diseases, which should be clarified by combining the patient’s morbidity form and relevant examinations. 1.If the patient suddenly develops unilateral weakness of legs and feet, accompanied by crooked mouth, clumsy language, numbness and weakness of upper limbs, it is considered to be caused by brain hemorrhage, cerebral infarction and other diseases. 2.If the patient has lumbar disc herniation The problem of lumbar spinal stenosis is formed when the patient is in a bad posture that easily leads to nerve root compression and the symptoms of leg and foot weakness. 3. Leg and foot weakness in elderly people over 80 years old may also be caused by arteriosclerosis and occlusion of lower limb blood vessels.