In order to optimize the tool coating material and reduce the tool wear rate, the coating material and wear mechanism for carbide tools are proposed and analyzed based on thermodynamics theory. We deduced the Gibbs free energy function method and analyzed the enthalpy value of the coating material of cemented carbide tools. The rules of diffusion wear and oxidation wear for WC-Co-based carbide tools were analyzed based on the diffusion dissolution theory and the calculation method of the thermal effect of chemical reaction. The diffusion wear and oxidation wear of WC-Co-based carbide tools when machining Ti-6Al-4V were studied with SEM-EDS. The results indicate that a good prediction accuracy of both diffusion wear and oxidation wear can be achieved by the method of thermodynamic theory analysis method. The conclusion will provide useful references for the optimization of cutting parameters and the improvement of the tool life.