The structure of the sole is quite complex, in a broad sense, it can include all the materials that constitute the bottom such as the outsole, the midsole and the heel. In a narrow sense, it only refers to the outsole, the common characteristics of the general sole material should have wear resistance, water resistance, oil resistance, heat resistance, pressure resistance, impact resistance, good elasticity, easy to fit the foot type, not easy to change after the shape, heat preservation, easy to absorb moisture, etc., but also with the middle sole, when walking to change the foot when the braking effect does not slip and easy to stop and other conditions. There are many kinds of materials for soles, which can be divided into two kinds: natural and synthetic materials. Natural substrates include natural bottom leather, bamboo, wood, etc. Synthetic substrates include rubber, plastic, rubber and plastic composite materials, recycled leather, elastic cardboard, etc