Preparation method of solar photothermal conversion coating

The invention provides a preparation method of a solar photothermal conversion coating, and belongs to the technical field of solar photothermal conversion coatings. The cleaned Cu is put into a vacuum chamber to be baked, the baking temperature cannot exceed 105 DEG C, and the baking time does not exceed half an hour but not less than 15 minutes; the two ends of the vacuum tube are each connected with an electrode, then the vacuum tube is filled with inert gas, direct-current voltage is connected to the electrodes, and Cu is cleaned through generated glow; a transition layer is plated on the surface of Cu in a medium-frequency magnetron sputtering mode; plating a high infrared reflection layer on the surface of the transition layer by using direct current magnetron sputtering; plating an absorption layer on the surface of the high infrared reflection layer by using intermediate frequency magnetron sputtering; and plating an antireflection layer on the surface of the absorption layer in a medium-frequency mag