The residual thermal stress (RTS) distributes heterogeneous and has complex interactions with the applied loadings, which significantly influences the mechanical properties of cemented carbides. The traditional experimental and simulation methods can only analyze the stress distribution statistically, and they cannot be applied in the study on the microstructure scale to get the detailed stress distribution. Using the finite element method, this study investigated the RTS in cemented carbides and the stress distribution under different loading conditions. Based on the stress analysis, it proposed a method to strengthen cemented carbides by tailoring their microstructures. The new approach presented in this study applies to stress analysis and microstructure tailoring for a broad range of multiphase composites.