Cold spray is a new surface engineering technology. In this paper, pure copper particles were sprayed on the Al substrate by this method and the copper coating was deposited sucessfully on the surface of the substrate. The microstructure of the coating and the interface between the coating and the substrate were observed by optical and scanning electron microscopes, and the phase was identified by XRD for the pure copper particles and the coating. The microhardness of the coating is measured. The results show that mechanical bonding is the main mechanism for the interface between the coating and the substrate, and there is a few metallurgical bonding for the interface; the coating is dense and its porosity is less than 0.4%; XRD results indicate that there is no oxidation occurred during the spray process. The microhardness of the coating is about 160Hv, which is higher than that of the as-casted copper.