Nickel-based superalloy GH4169 is of special material properties, resulting in large cutting force, high cutting temperature, serious work hardening, tool–workpiece adhesion and tool wear during machining processing of GH4169. Therefore, it is beneficial to controlling tool wear by studying the tool wear mechanism during the process of TiAlN coated carbide tool’s orthogonal turning of GH4169 at different wear stages. Firstly, the orthogonal turning experiments were carried out with GH4169 disc as workpiece and TiAlN coated carbide tool as cutting tool on the CNC lathe, to obtain the tool wear states under different wear stages. Secondly, the tool wear surface was observed by scanning electron microscopy (SEM) and chemical composition of the tool wear surface material was analyzed. Thirdly, the existence of chemical wear of cutting tools was verified by X-ray diffraction (XRD) phase composition analysis. Finally, the tool wear control measures were proposed by combining the full-stage tool wear mechanism and tool wear rate model. The results show that the adhesive wear, abrasive wear, diffusion wear and chemical wear occur during the orthogonal turning of GH4169 by TiAlN coated carbide tools under the selected cutting conditions. The main tool wear mechanisms in the initial wear stage are adhesive wear and abrasive wear while those in the normal wear stage and sharp wear stage are adhesive wear and diffusion wear. Tool wear could be controlled by accelerating decreasing rate of abrasive wear in the initial wear stage or reducing diffusion wear rate in the normal wear stage.