Multi-density replaceable built-in insole

The multi-density replaceable built-in insole comprises an insole body, a cushioning unit is arranged on the lower portion of the insole body, and a shock absorption unit is arranged on the lower portion of the cushioning unit; the density of the shock absorption unit is larger than that of the insole body, the density of the insole body is larger than that of the shock buffering unit, when the insole is stressed, the deformation quantity of the shock buffering unit is large, the foot can be buffered, the deformation quantity of the shock absorption unit is small, and the supporting and shock absorption effects on the foot can be achieved. The multi-density replaceable built-in insole is simple in structure and convenient to use, when the buffering performance of the insole cannot meet the requirement, the insole can be directly and integrally replaced, and the service life of a shoe is prolonged; the insole is made of three materials with different densities, the buffering effect is good, the shock absorptio