Abstract: A nickel-based graphene composite electroforming layer was prepared under supercritical and ordinary conditions, respectively. The effects of two preparation conditions and graphene oxide (GO) mass concentration on the microstructure, surface morphology, hardness and wear resistance of the composite electroforming layer were investigated. The results show that comparing to those under the ordinary condition, the microstructure of the composite electroforming layer under the supercritical condition was compact and the surface roughness was lower; the preferred degree of the Ni crystal face (111) and (220) decreased while that of the crystal face (220) increased; the hardness and wear resistance were improved. Under the supercritical condition, with the increase of the GO mass concentration, the microhardness, wear resistance and the embedding amount of graphene nanosheets all first increased then decreased. When the GO mass concentration was 0.20 g·L^-1, the graphene content in the composite electroforming layer was the highest, and the microhardness reached the largest value of 768 HV, also the relative wear resistance was the best.