Three kinds of TiN-Ni cermets containing Ni 30vol%, 50vol% and 70vol% were prepared by hot pressing sintering method. The continuous oxidation behavior of TiN-Ni cermet at 800 C in static air was studied. The results show that there is no chemical reaction between the TiN phase and the Ni phase during the sintering process, and the adjustment of Ni content contributes to the densification of sintering. The density of TiN/70Ni is the highest, up to 99.6%, which helps to strengthen its high temperature oxidation resistance. Scanning electron microscopy (SEM), energy spectrum analysis (EDS) and X ray diffraction (XRD) were used to study the mechanism of high temperature oxidation of TiN-Ni composites. The oxidation process was divided into rapid oxidation process and slow oxidation process, in which the external diffusion of metal ions and internal diffusion of oxygen ions existed.