In order to realize the resource utilization of high-aluminum fly ash and alleviate the huge demand for catalyst carriers, this work developes a new process. That is, using Chinese characteristic high-alumina fly ash as raw material, the mullite-corundum catalyst carrier is prepared by the acid-alkali combined method, and a series of characterization methods such as specific surface automatic physical adsorption instrument (BET), scanning electron microscope (SEM), X-ray diffractometer (XRD), inductively coupled plasma mass spectrometer (ICP-OES) are used for in-depth analysis. The results show that when the acid-alkali combined process is adopted, that is, the acid process conditions are sulfuric acid concentration 1.5 mol/L, the reaction temperature 85℃, liquid-to-solid ratio 7, and the reaction time 90 min; subsequent pretreatment alkali process conditions are NaOH concentration 200 g/L, reaction temperature 95℃, liquid-to-solid ratio 15, and reaction time 150 min, the leaching rate of silica reaches 58.51%, and the leaching rate of amorphous silica is 83.49%. The obtained catalyst carrier with mullite and corundum as the main components has a higher specific surface area and water absorption. They are 39.35 m2/g and 70.01%, respectively. Its heat-resistant temperature reaches 1100℃, revealing that it has the advantages of good heat stability. From the SEM pictures, it can be seen that particle size is between 20~50 μm, and porous spherical structure is bonded by short rods. The X-ray diffraction characterization results show that the carrier mineral phase contains only mullite and corundum, indicating that it has good chemical stability and mechanical strength. The pore distribution analysis results reveal that the catalyst carrier has a wide pore size distribution, and the pore size is mainly 10 nm around. A mullite-corundum catalyst carrier with excellent performance has been prepared successfully, as finding a new way for the high-value utilization of secondary resource fly ash.