Abstract: The one-step sintering method was used to study effect of TiN addition on the microstructure and properties of cemented carbide by changing its amount in the raw material. Scanning electron microscopy (SEM), energy dispersive spectrometry (EDS), X-ray diffraction analyzer (XRD), surface roughness analyzer, and scratch tester were selected to investigate the effect of TiN addition on the physical-mechanical properties, microstructure, phase composition, surface topography and coating adhesion of WC-TiC-TaNbC-10Co cemented carbide. The results showed that with TiN content increasing in the range of 0~1.6%, the magnetic saturation and density of the carbide decreased, and its coercive, hardness, and bending strength increased. The thickness of its cubic carbide-free layer increased, surface roughness decreased first and then increased, and the adhesion strength of the CVD coating increased first and then decreased. The best CVD coating adhesion strength was detected for the cemented carbide with the TiN of 0.8%.