Micro-nanostructure coatings have been attempted to prepare by Electro-spark deposition (ESD) on cast iron substrate. The microstructures and properties of the coating were investigated by X-ray diffractometer (XRD), scanning electron microscopy (SEM) and microhardness tester. The results show that micro-nanosized particles and fine equiaxed structures prevail in the coating. The primary phases of the coating contain Fe3W3C, Co3W3C, Fe7W6 and W2C. Its average microhardness reaches 1290.1 HV. The results of abrasive test demonstrated that the coating had an excellent sliding wear resistance because the superfine particles distributed dispersedly in the coating increased the resistance to micro-cutting and plowing during the wear test, which effectively improves the surface performance of cast iron substrate.