The invention discloses instant mushroom soup powder. The instant mushroom soup powder is prepared by uniformly mixing 100 parts of concentrated mushroom soup powder, 2 parts of white granulated sugar, 6 parts of table salt and 300 parts of maltodextrin. The instant mushroom soup powder is prepared through the steps of adopting dried mushroom powder, adding water for ultrasonic treatment, performing enzymatic hydrolysis, enzyme deactivation, secondary enzymatic hydrolysis, secondary enzyme deactivation, concentration by centrifuging and vacuum drying. A two-time enzymatic hydrolysis technologyis adopted by the invention, papain and cellulase are adopted in the first-time enzymatic hydrolysis for synergistic enzymatic hydrolysis to rapidly decompose and break cell walls, and umami substances are fully released; neutral protease and flavourzyme are adopted in the second-time enzymatic hydrolysis to mainly cut off peptide chains from the insides and outsides of protein molecules, so thatpresented bitter peptide is fully hydrolysed to remove the bitter taste of mushroom soup, and the purposes that the product umami is improved, the bitter taste is removed, and good quality of a product is shown are achieved. The flavor and umami of the mushroom soup powder are preserved to the greatest extent in a vacuum drying mode, substances of sodium glutamate, edible essence and the like arenot added, and the instant mushroom soup powder is a convenient and timely instant mushroom soup powder product.