The difference between flat feet and normal feet is mainly manifested in appearance and function, and compared with normal feet, flat feet are more prone to foot discomfort and related diseases. 1. Appearance: Normal feet have arches, so the soles of the feet are arched, which can cushion the ground force and prevent the blood vessels of the soles of the feet from being compressed; whereas flat feet do not have arches, so the dorsum of the feet is flat, and the forefoot is relatively wide. 2. Function: Compared with normal feet, patients with flat feet have poorer athletic ability, which is mainly manifested in the decrease of running and long-distance jumping ability; in addition, patients with flat feet are more likely to feel discomfort and fatigue when walking for a long time. 3. Diseases: Compared with normal feet, patients with flat feet are more prone to plantar tendonitis and osteomalacia due to the lack of arch structure. Parents are advised to bring their children to regular hospitals as soon as possible for corrective treatment under the guidance of doctors.