Abstract: The paper introduces the principle and some feasible structures of dielectric wall accelerator (DWA). By the study of electromagnetic scattering of multilayer dielectric cylinders, the relation of scattering width, parameters of materials and structure of beam pipe of DWA is investigated with FORTRAN program, for designing the accelerating beam pipe of DWA with high accelerating gradient and high energy coupling efficiency. The results confirm that，with permittivities of dielectric cylinders fixed, the scattering width becomes larger when the radiuses get larger. With radiuses of dielectric cylinders fixed, the scattering width shows no obvious change when the permittivities become larger, but the minimal scattering width becomes smaller. When the radiuses and permittivities of the first