Abstract: TiN metal matrix composite coating was deposited on 45 steel substrate with the home-made special gas-filled-closed electric-spark deposition device and electric-spark deposition machine modeled DZ-1400, and the industry pure titanium (TA2) was used for electrode and the industry pure nitrogen for shielding and reactive gas.The phase of coatings was analyzed using X-ray diffractometer.The microstructure of coatings was investigated with scanning electron microscope.The microhardness of coatings was tested by hardness-testing device.The wear-resisting property of coatings was compared with that of W18Cr4V rapid steel treated by quenching using the home-made abrasion machine.The results indicated that excellent bonding between the coating and the carbon steel substrate is ensured by the strong metallurgical interface.The coatings was mainly made up of Ti coming from electrode, TiN ceramic particle synthesized in-situ and Fe coming from substrate.The average microhardness of coating is 1 323 HV0.1 and its wear-resisting property is better than that of W18Cr4V rapid steel treated by quenching.