The invention discloses a preparation method of a macroporous alumina carrier. The method comprises the following steps: (1) preparing a solution containing grease and organic acid, an acidic aluminum solution and a basic aluminate solution, and respectively marking into a solution A, a solution B and a solution C; (2) combining the solution B and the solution C to perform gelation reaction, regulating pH to be 9.0 to 11.0, wherein the pH is preferably is 9.5 to 10.5; controlling the reaction temperature to be 60 to 95 DEG C, wherein the reaction temperature is preferably 75 to 85 DEG C; performing ageing, filtering, washing and drying after the gelation reaction, wherein the solution A is added before or during gelation; the solution A, the solution B and the solution C are preferably combined to perform the gelation reaction; (3) forming the material obtained in step (2), and then drying and roasting to obtain the macroporous alumina carrier, The macroporous alumina carrier prepared by the method has the advantages of being large in aperture, large in pore volume and high in strength.