Abstract: To investigate the effect of different coatings on the tool life when machining TC4 titanium alloy, the article fabricates experimental tools by coating the same type of substrate with TiAlN and TiB₂ coatings, respectively, and conducts side milling comparative tests. It analyzes the impact of different coatings on the wear morphology and failure mechanism of the tools when machining TC4 titanium alloy. The tool life is determined by the criterion of a flank wear width of 0.2 mm. The experimental results indicate that the tool life of TiAlN coated tools when machining TC4 titanium alloy is approximately 116% of that of TiB₂ coated tools. This study can provide data support for tool design and optimization.