Abstract: During the long-term service period, the drilling bit is subjected to multiple factors such as mechanical impact, abrasive wear, drilling fluid erosion, and formation corrosion. As a result, it will experience multiple failure behaviors including wear and breakage of cutting teeth, erosion of the matrix, and fatigue cracking of the structure. The TiN-based coating has the characteristics of wear resistance and corrosion resistance. By precisely controlling the preparation parameters, multiple-component gradient structure protective coatings can be obtained, which can alleviate the thermal stress and impact stress at the interface between the film and the substrate, prevent cracks from extending into the substrate, and isolate the abrasive erosion and corrosive medium from contacting the substrate. This paper briefly describes the types of current mining drill bits and their working environments, summarizes the methods for improving the performance of the drill bit body. It elaborates on the strengthening mechanism of the TiN coating and the development direction of hard coatings. It also looks forward to the future research directions of hard coatings and drilling bits.