The hazards of flat-footedness can cause lower limb weight-bearing force point change, Achilles tendon inflammation, etc., as follows: 1, lower limb weight-bearing force point change: it can cause many soft tissue diseases of the foot, for example, flat-footedness can cause the plantar tendon membrane to increase the force and overload, which can easily cause plantar tendonitis, that is, after a short period of time or a small amount of walking, it can appear the pain of plantar heart. 2, Achilles tendon inflammation: due to the flat-footedness, it can often cause the Achilles 3, Fracture: the longitudinal arch and transverse arch of the foot collapses when flatfooted, and the metatarsal bones are subjected to more cumulative strain when walking too much, which can easily cause pathologic fracture of the metatarsal bones or marching fracture.