Active screen plasma nitriding (ASPN) is an emerging surface engineering technology that offers many advantages over the conventional DC plasma nitriding (DCPN). In this research, plasma nitriding of H11 tool steel, using titanium active screen was investigated. Samples were plasma nitrided at 550oC, for 10 and 20 h with 3 different gas mixtures of H2/N2% = 3, 4, 5. The coating microstructure and phase analysis were investigated using Scanning Electron Microscopy (SEM) and X-ray Diffraction techniques. The dominant phase in the compound layer was TiN. With increasing processing time, the layer thickness was increased. According to SEM results, the sample surface was formed of nano sized and particulate titanium nitride particles. It was shown that with increasing H2% in gas mixtures, better surface quality, golden yellow color, was obtained. Also, the intensity of TiN peaks and layer thickness were increased significantly.