Flat feet are categorized into congenital flat feet and acquired flat feet, and the common causes include heredity and posterior tibial tendon insufficiency. 1. Congenital flat feet: mainly related to genetic factors, tarsal coalition and bony deformities, soft tissue lesions and other congenital vertical talus. Among them, tarsal coalition is a rare skeletal developmental deformity, and it is more common in the middle heel talar tarsal coalition and heel navicular tarsal coalition. 2. Acquired flat feet: the more common cause is tibialis posterior tendon insufficiency, followed by foot trauma, foot metatarsal tarsal injury and other bone and ligament injuries, rheumatoid arthritis, osteoarthritis tuberculosis and other bone diseases of the foot, and neuromuscular pathology caused by poliomyelitis. When the local bone degenerative changes, can also induce acquired flat feet. In addition to the above reasons, overwork, long-term heavy standing, weight gain and other functional injuries can also be induced by acquired flat feet. It is recommended that patients with flat feet actively cooperate with doctors, choose the right size of shoes for daily use, pay attention to rest after proper exercise or walking, and massage the soles of the feet appropriately.