Abstract: In order to determine the temperature field of WC-12Co coating, mathematical model of heat conduction was established by utilizing suitable heat source and the thermal boundary conditions. Numerical simulation was carried out by commercial finite element code ANSYS, and iso-surface, the temperature distribution curve and temperature variation curve were derived. The areas of melting and gasification zone were measured by setting of contour lines of temperature field. Furthermore, the influence of process parameters on the areas of melting and gasification zone was researched and the optimized process parameters were predicted. To verify the prediction, electro spark deposition experiments were carried out and the optimized process parameters were determined.