The invention belongs to the technical field of 
ceramic matrix composite materials, and particularly relates to a preparation method of an 
alumina fiber reinforced high-temperature-resistant anti-scouring 
thermal insulation material. The preparation method comprises the following steps: S1, preparation of an aluminum 
oxide preform; S2, preparation of 
slurry of a high-temperature-resistant 
coating;S3, preparation of a high-temperature-resistant 
coating of the aluminum 
oxide preform; S4, preparation of a 
composite material blank. According to the method, the aluminum 
oxide preform is soaked inthe modifier, and after soaking is completed, the 
slurry obtained in the step S2 is soaked and / or coated and / or deposited on the modified 
green body, so that the high-quality high-temperature-resistant 
coating can be quickly, efficiently and uniformly obtained through the design; and the material which can meet the requirements of high-
temperature resistance, anti-scouring, heat preservation, heatinsulation and high-
temperature resistance, anti-scouring, heat preservation and insulation at the same time is prepared by matching with a subsequent process. The method is reasonable in step design, simple and controllable in process and convenient for large-scale industrial application.