The Cu-coated nano SiC composite particles were prepared by heterogeneous nucleation method. For the heterogeneous nucleation process, the dispered nano SiC particles and the active Cu2O precipitation were both prefabricated. The composite particles were characterized by means of XRD, SEM, EDS, TEM and ED analysis technics. It is found that Cu layers are coated on the nano SiC particles, which are continuous and dense, and partly oxidized to Cu2O, and the oxidation rate can be reduced by improving experimental processes. The investigation on reaction mechanism shows the disproportionating reaction speed of Cu+ can be controlled by adjusting the pH value of reaction solution, which makes the degree of supersaturation of Cu crystallites accord with the conditions of heterogeneous nucleation.