The invention relates to a preparation method for a super-thick energy absorption coating layer. The preparation method comprises the steps that S01, a substrate is subjected to gas ion source cleaning; S02, the substrate is subjected to high-power pulse metal ion cleaning; S03, acetylene and nitrogen are injected for CrAlNC deposition; S04, an acetylene valve is closed, and ZrN is deposited through high-power pulse magnetic control; S05, the nitrogen is stopped, and the acetylene is injected for CrAlC deposition; and S06, a film layer is circularly deposited till the thickness of the film layer is larger than 20 [mu]m. According to the preparation method provided by the embodiment of the invention, through the mode of combining a gas ion source technology and a high-power pulse magnetic control technology with a multi-arc ion plating technology, the deposited super-thick coating layer is small in internal stress and good in toughness, impact resistance and energy absorption performance. The preparation method is simple, easy to implement, low in cost and high in efficiency, and then is quite suitable for batch production.