TC4 titanium alloy was cut in high-speed under dry and minimal quantity lubrication (MQL) conditions, with TiAlN-F, AlTiN-ML and (nc-AlTiN)/(a-Si3N4) carbide coating tools. Tools life were compared, tools wear and failure modes were analysed, tool wear mechanisms were studied. The results showed that different coatings had little effect on tool life under dry cutting condition. Under the MQL（Minimal Quantity Lubrication） condition, the coating could significantly reduce tool wear and improve tool life, and (nc-AlTiN)/(a-Si3N4) coating has the best performance. In high-speed cutting of TC4 titanium alloy, wear mechanism was more complex, due to the interaction of various tool wear patterns. Adhesive wear, oxidative wear, diffusion wear, abrasive wear were main tool wear, chipping and coating spalling were main failure modes.