Abstract: It is a powerful and efficient method for materials development and process optimization by gasping the thermodynamic and kinetic information of studied materials and further performing simulations. The quality of CALPHAD-type calculations is strongly dependent on the quality of the thermodynamic and diffusivity databases. Based on previously developed thermodynamic database (CSUTDCC1) and diffusivity database (CSUDDCC1), some simulations concerned during the research and development of cemented carbides, like sintering “carbon window” and cubic phase composition, were performed. Several gradient cemented carbides sintered under vacuum and various partial pressures of N2 have been studied. The microstructure and element concentration in the gradient layer were investigated via SEM and EPMA. Thermodynamic and kinetic simulations were performed and agreed well with experimental data. Examples of thermodynamic and kinetic simulation applications in design and manufacture for gradient cemented carbides were shown, which provides theoretical basis for the development of novel and high-performance gradient cemented carbides.