Abstract: The invention provides a preparation method of an ultra-thick Ti2AlC coating. The invention adopts multi-arc ion plating technology (AIP) and magnetron sputtering technology composite, utilizes high-speed Φ155 large arc source deposition technology, can obtain a dense coating with large thickness in a short time, and first prepares a transition layer, so that the coating has excellent binding force with a substrate; The invention adopts TiAl target as cathode arc source and graphite as magnetic control target material, avoids amorphous phase generated by gaseous carbon source and hydrogen ion introduction, avoids short plate with high cost of Ti2AlC composite target, adopts sub-target composite deposition, obtains Ti2AlC coating with large thickness in one step, and also reduces tedious steps of secondary treatment of workpiece by two-step method. The experimental results show that the preparation method provided by the invention can obtain an ultra-thick Ti2AlC uniform layered phase structure coating with a thickness of more than 10 μm in one step, the coating is compact and flat, and the binding force is more than 60N.