The invention discloses a method for preparing black rice enzymatic hydrolysate. The preparing method comprises the following steps of, conducting extrusion expansion and grinding to black rice materials to prepare puffed black rice micro powder; adding the black rice micro powder with purified water to prepare puffed black rice paste; conducting liquidation to the puffed black rice paste by adopting alpha-amylase; after liquidation, conducting combined enzymolysis to the puffed black rice paste by cellulase and glucoamylase to prepare black rice enzymatic hydrolysate. Prepared black rice enzymatic hydrolysate helps not only with digestive absorption of black rice products but also with effective release and reservation of polyphenol substances black rice cortex. Prepared black rice enzymatic hydrolysate and an auxiliary material such as lycium barbarum juice are compounded into black rice polyphenol compound beverage respectively with the weight percentage of 60%-80% of black rice enzymatic hydrolysate and the weight percentage of 20%-40% of lycium barbarum juice, and black rice polyphenol and lycium barbarum polysaccharide are enriched in the black rice polyphenol compound beverage.