Abstract: This paper investigates the topology optimization of thermo-elastic structure for maximizing thestructure stiffness with the volume constraint and the uniform temperature distribution. Firstly, theinfluence of both the thermal loading and the mechanical loading on optimal design is studied.Secondly, Comparison of the effect of eliminating the intermediate density between power lawSIMP (Solid Isotropic Material with Penalization) and RAMP (Rational Approximation ofMaterial Properties) is made. The difficulties of the non-monotonous behavior of the complianceand the intermediate density of optimal solution arise from the same penalization to both thetemperature loadings and the force loadings. To resolve these problems, the new approach with thedifferent penalization to the different loading is developed to eliminate the intermediate density.Numerical results show that the proposed method is valid for the design of thermo-elasticstructure.