This paper aims to improve the density of TiBx coatings and optimize the mechanical properties of TiBx coatings. TiBx coatings are prepared under different substrate bias conditions by mid-frequency magnetron sputtering technology (mfMS), and the evolution of microstructure and mechanical properties of TiBx coatings under different substrate bias is explored. The oxidation resistance and high-temperature tribological performance of the TiBx coatings are analyzed. The chemical composition of TiBx coatings is characterized by electron probe microanalysis. The surface topography, cross-sectional topography, and thickness of TiBx coatings are characterized by scanning electron microscopy. The preferred orientation of TiBx coatings is evaluated by X-ray diffractometer. The residual stress of TiBx coatings is tested by the sin2ψ method. The hardness and elastic modulus of TiBx coatings are measured by nanoindenter. The adhesion of TiBx coatings is evaluated by the scratch method and the Rockwell C indentation method. The high-temperature tribological performance of TiBx coatings is evaluated by ball-on-disk friction tester. The high-temperature oxidation resistance of the coatings is characterized with a muffle furnace in an air environment. The results show that the prepared TiBx coatings show a significant (001) preference orientation. As the bias increases, the grains of the TiBx coatings are refined, and the density of the TiBx coatings is increased. As the bias increases, the residual stress of the TiBx coatings gradually increases, reaching a maximum of ?5.9 GPa. The hardness and the elastic modulus of the TiBx coatings gradually increase with the increase of the substrate bias pressure. The hardness of TiBx coatings reaches the highest 39.1 GPa, and the elastic modulus of the TiBx coatings reaches the highest 421.7 GPa. As the bias pressure increases, the adhesion strength of the coatings gradually decreases. When the substrate bias voltage is ?70 V, the adhesion of the coatings is HF1 class and the critical load FLc3 is 90.9 N. When the substrate bias voltage is ?100 V, the adhesion of the coatings is HF1 class and the critical load FLc3 is 71.6 N. But at a substrate bias voltage of ?130 V, the adhesion of the TiBx coatings is significantly reduced to HF3 class and the critical load FLc3 is reduced to 40.9 N. At temperature lower than 600 ℃, no new phase formation is found in the TiBx coatings, and there is still an obvious TiB2-(001) preferential orientation. With the increase of temperature, the friction coefficient of TiBx coatings first increases and then decreases, reaching a maximum of 0.82 at 500 ℃ and a minimum of 0.65 at 600 ℃. The wear rates of the TiBx coatings at different temperature are all about 0. With the increase of substrate bias, the bombardment effect of film-forming ions is enhanced, which promotes an increase in density and grain refinement of the TiBx coatings. As a result, with the increase of substrate bias, the residual stress and nanohardness of the TiBx coatings gradually increase, and the adhesion of the coatings monotonically decreases. At temperature below 600 ℃, the TiBx coatings have excellent oxidation and abrasion resistance.