Molybdenum alloying or modified layer was fabricated on the H13 steel substrate by electronic spark deposition technique (EDS). The microstructure, element distribution and microhardness of the modified layer were analyzed using metalloscope, X-ray diffraction (XRD), Glow Discharge Optical Emission Spectroscopy (GDOES) and microhardness tester, respectively. The modified layer is composed of white layer, diffuse layer and heat affected zone. The interdiffusion between Mo element and other elements in H13 substrate results in Metallurgical bonding. Microhardness of the coating is 1482HK0.025 which is 5 times higher than that of H13 steel base (280HK0.025). The ball-on-disc dry sliding test indicates that the friction coefficient of H13 substrate is decreased obviously by the molybdenum modified layer. The wear mass loss of Mo modified H13 substrate is only one seventh of that of the substrate. The wear resistance of H13 is improved significantly by the Mo modified layer.