Abstract: In overlong structure design, the temperature stress of walls caused by temperature field changes should be analyzed in order to control temperature cracks in the walls. For single-layer walls subjected to periodic harmonic heat, the heat transfer differential equation in the first boundary condition was solved by a variable separation method, and the analytical solution for the temperature field of a single-layer wall was received. Based on this solution and the assumption that the temperature and heat flow at the contact interface of two layers are equal, the analytical solutions of a temperature field of a multilayer wall was obtained while cconsidering the heat exchange between the wall and the air, and provided a theoretical basis for the temperature stress analysis and crack controlling in walls. Using this formula for the temperature field in walls, the temperature field in the external insulation wall was researched.