The invention discloses a preparation device and a preparation method of a macroporous diamond drawing die coating. The preparation device includes a CVD device, in which a rotational workbench, which is driven to rotate by a power device, and a drawing die, which is vertically mounted on the rotational workbench, are installed. A heating wire assembly is fixedly installed in an inner hole of the drawing die and includes two semi-annular molybdenum pieces and a plurality pairs of vertical heating wires which are arranged symmetrically on the two semi-annular molybdenum pieces. The end of each vertical heating wire is connected to one semi-annular molybdenum piece. The two semi-annular molybdenum pieces are respectively connected to a lamp filament electrode. By means of the structure, the preparation device is reasonable in design, so that the drawing die is very strong in wear resistance, is long in service life, is greatly reduced in cost, is improved in product quality, can be used for reducing the thickness of a metal tube wall, determining the diameter of a metal tube and the like, and can be used as a compression die.