Abstract: In order to increase the surface strength and wear resistance of the parts,TiC-TiB2 reinforced Co-based composite coating was successfully in situ synthesized by laser cladding with preplaced powder method on steel Q235 using TiO2,Al,B4C and KF-Co50 alloy powders as the binding material.The microstructure and phases analysis of the coating were performed with metallographic microscope,scanning electron microscope and X-ray diffractometer.The microhardness and wear resistance of the coating were also tested.The results show that the coating is uniform,continuous and free of pores and cracks.An excellent bonding between the coating and the substrate was ensured by the strong metallurgical interface.The microstructure of the coating is mainly composed of γ-Co,TiC,TiB2 and Cr23C6.The average microhardness of the coating is 770HV0.2 and the coating presents excellent wear resistance.The results have positive significance to improve service life of the parts.