The high-temperature alloy Inconel 718 was a typical difficult-to-machine material. In this paper， DEFORM-3D software was used to carry out the simulation test of drilling high-temperature alloy Inconel 718 with uncoated， TiC single-coated and TiC/Al2O3 composite coated carbide tools. The cutting performances of composite coating tools under different drilling conditions were researched and were verified by drilling experiments. The results show that the TiC/Al₂O₃ composite coating tool can effectively reduce the drilling axial force and the drilling temperature， the maximum reduction of the axial force is 20%， and the maximum reduction of the drilling temperature is 35%. The accuracy of the simulation model is verified by drilling experiments， and a certain reference for the selection of coating types and drilling parameters in the actual drilling of high-temperature nickel-based alloy Inconel 718 is provided.