Abstract: In order to find the optimum load reduction effects and complete design methods,new load reduction tests in site on the top and lateral sides of a culvert by using EPS slabs with different thicknesses are done based on the previous tests. The test results indicate again that the EPS slabs can reduce vertical and lateral soil pressures acting on the culvert obviously by the compressive deformation of the EPS slabs; the thicker the EPS slabs,the smaller the soil pressure on the culvert; but the load reduction effects decrease with the increase of thickness of EPS slabs. The settlement of the culvert decreases after adopting the load reduction method,thereby different settlements along the longitudinal culvert are improved. According to the load reduction theory developed by the authors before,a simple design method for load reduction by using EPS slabs is put forward. The corresponding design and application conditions,incision,placing and construction methods of EPS are also given.