The invention relates to a solar-energy selective absorption coating and its preparing method. The coating is structured in double layers or three layers: the first layer is a polished stainless steel substrate, the second layer is a Cu1.5Mn1.5O4 composite oxide absorption layer, the third layer is an anti-reflection coating formed by a TiO2 film, and the three layers are arranged from bottom to top. The absorption layer and the anti-reflection coating are both prepared by steps of dip-pulling plating by a sol-gel method and annealing. The preparation method of the coating contains steps of composite oxide absorption layer preparation and anti-reflection coating preparation, wherein a preparation method of the composite oxide absorption layer contains the step of sol and thin film preparation and a preparation method of the anti-reflection coating contains steps of composite oxide absorption layer surface cleaning, sol preparation and anti-reflection coating thin film preparation. The coating provided by the invention has visible-near infrared high absorptivity, mid-far-infrared low emissivity and good high temperature resistance and corrosion resistance, is suitable for the operating temperature of 100-500 DEG C, and simultaneously requires a simple production technology and low processing cost.