NOVELTY - Preparation of medium-high temperature solar energy selective absorbing coating comprises preprocessing substrate; depositing infrared reflecting layer, which comprises molybdenum (Mo), on substrate; depositing absorbing layer on the infrared reflecting layer by depositing molybdenum (Mo) by Mo target direct current magnetron sputtering and depositing aluminum nitride (AlN) by Al target medium frequency reactive sputtering method; and depositing antireflection layer on the absorbing layer by continuously performing medium frequency magnetron control sputtering of AlN film.    USE - Preparation of medium-high temperature solar energy selective absorbing coating (claimed).    ADVANTAGE - The method is simple, easy to control, and conducted in a short period; and has convenient operation and fast sputtering speed.    DETAILED DESCRIPTION - Preparation of medium-high temperature solar energy selective absorbing coating, which comprises three layers of film, which are infrared reflecting layer, absorbing layer, and antireflection layer from substrate to surface, where infrared reflecting layer comprises Mo film, absorbing layer comprises first sublayer and second sublayer, which are composed of Mo+AlN film, antireflection layer comprises AlN film, and argon (Ar) gas is used as sputtering gas, comprises medium frequency magnetic control sputtering or direct current magnetic control sputtering method. It comprises preprocessing the substrate by carrying out a series of surface treatment to the substrate, which are polishing, alcohol and acetone ultrasonic cleaning, and deionized water ultrasonic cleaning in sequence, drying and placing into magnetic control sputtering chamber, and ion bombarding the surface of the substrate, enhancing the bond between substrate and infrared reflecting layer; depositing the infrared reflecting layer on the substrate comprising preparing the surface of substrate, taking Ar gas as sputtering gas for producing Mo film, and controlling the thickness of the infrared reflecting layer at 50-200 nm; depositing the absorbing layer on the infrared reflecting layer comprising depositing Mo by Mo target direct current magnetron sputtering, depositing AlN by Al target medium frequency reactive sputtering method to form first layer of metal ceramic layer i.e. first sublayer of absorption layer, where thickness of Mo+AlN film for preparing the first sublayer on the infrared reflecting layer is 30-150 nm, increasing AlN depositing amount by increasing the flow of Ar reaction gas in medium frequency sputtering, at the same time reducing the direct current magnetic control sputtering power to reduce the Mo film depositing amount, and preparing second sublayer i.e. Mo+AlN film with thickness of 30-150 nm; and depositing the antireflection layer on the absorbing layer comprising stopping Mo target direct current magnetron control sputtering, and continuously performing medium frequency magnetron control sputtering of AlN film, where thickness of antireflection layer is 30-100 nm.