In order to obtain more excellent and comprehensive composite coatings, Ni-Co-graphene composite coatings of different graphene particle sizes were prepared by using composite electrodeposition technology, and Ni-Co alloy coatings were prepared. The surface morphology, phase structure, microhardness, wear resistance and corrosion resistance of the coating were tested. The results showed that graphene was well embedded in the coating matrix during electrodeposition, and the presence of graphene did not change the crystal structure of the coating matrix. The addition of graphene increased the microhardness of the composite coating up to 805HV. The friction coefficient of composite coating is reduced, and the adhesive wear area is reduced to some extent. The self-corrosion current density of composite coating can be reduced to 1.0905×10-5A/cm2, which is lower than that of Ni-Co alloy coating. It was shown that the addition of graphene enhanced the hardness, wear resistance and corrosion resistance of the composite coating.