In this research, a nickel-base powder reinforced with tungsten carbide particles (micron size) was applied by Plasma Transferred Arc (PTA) process on the surface of tool steel to improve surface characteristics to improve its lifetime in working condition. The Design of Experiment (DoE) method was applied to find optimum combination of hardfacing parameters and to minimize the number of weld runs. Current, travel speed and preheat were considered as variable parameters. These parameters are important to reach a final layer with an appropriate bead geometry accompanied with good metallurgical properties. All samples were prepared for microstructural investigations and the effect of process parameters on the weld bead geometry was considered. For each weld overlay, weld bead geometry parameters were measured including dilution, penetration and reinforcement. Microstructures and the distribution of tungsten carbide particles after welding were analyzed by Scanning Electron Microscopy (SEM) equipped with an EDS microprobe. In addition, X-ray diffraction analysis was performed to find the existing phases after welding. Also, to observe the distribution of each WC in the matrix 3D optical profilometry analysis was performed. At the end, among all the experiments, the best sample with appropriate bead geometry and microstructure was selected.