The interfacial bonding strength and its influential factors between the electroless SiCp/Ni-P composite coatings and steel substrate are investigated in this paper.It is found that the component and stress status in the layer 5μm thick over the coating/substrate interface play a dominant role in controlling the interfacial bond,Beyond this layer, the change of SiCp sizes has no influence on the bond.An appropriate heat treatment can improve the bond.