Pain on the bottom of the foot in flat shoes has the following causes: first, if the sole of the shoes worn is too hard and thin, even flat shoes cannot achieve the role of protecting the soft tissues of the sole, which can still lead to excessive pressure on the plantar fascia extrusion, causing painful symptoms; second, flatfoot disease, if the patient suffers from flatfoot disease, the longitudinal arch of the foot will collapse, the plantar fascia is overloaded, such as insisting on long or long-distance Walking, even wearing flat shoes will cause plantar pain; third, if the forefoot transverse arch collapse occurs, it is not normal to walk for a long time or a long distance. If you insist on excessive walking, even wearing flat shoes will still lead to plantar pain. This shows that arch abnormalities should be adjusted for the arch, such as wearing only flat shoes can not completely prevent plantar pain.