By means of model test and 3D numerical simulation, discusses the working behaviors of gravel cushion and reinforced gravel cushion in the soft soil foundation respectively, and analyzes effects of the parameters of cushion thickness, geogrids and geogrid layers on the deformation modulus, vertical stress field and settlement deformation of gravel cushion and reinforced gravel cushion. The research results indicate that: 1）The stress diffusion effect of the reinforced gravel cushion of geogrids is obviously stronger than that of pure gravel cushion; 2）The internal stress of the cushion develops from bottom to top. When applying a small load, the cushion bottom appears stress concentration phenomenon, with the increase of load, the stress concentration area moves closly to the top of cushion; 3）With the increase of geogrid layers, the stress-concentration range and the settlement of reinforced gravel cushion reduced.