The work aims to study the method to obtain the dynamic cushioning characteristic curve of liners of different densities to get the change law of material property, in order to enhance the test efficiency. The dynamic compression tests for EPS of different densities were conducted. Based on the comparison of constants a and b of stress-energy equation under different densities of key materials, the changing curves of material constants under different densities were fitted to analyze the change trend of values a and b under different densities of materials. Through multiple curve fittings of different function types and comparative analysis, the values a and b of stress-energy equation and the specific polynomial mathematical relationship were acquired for the different densities of liner materials. The stress-energy equation and the change trend functions of constants a and b of EPS materials are obtained, from which the dynamic cushioning curve under any density of the same liner can be obtained.