Abstract: To discuss the adaptivity of track substructure of high-speed railway, the historical development of the structural analysis and design of track substructure was reviewed as the numerical analysis basis of the structural behavior of ballastless track substructure with a case study of Sui-Yu (Suining-Chongqing) high-speed railway. Dynamic responses of track substructure under the action of train loading were investigated using a finite element software, and the effects of train speed, axle loading and trackbed elastic modulus on the dynamic stress, vertical deflection and vertical acceleration of track bed were researched. The research results show that a sound track bed is essential to assure structural integrity and performance of railway lines and an asphalt railway substructure may be a good alternative.