The invention provides an aluminum oxide ceramic precursor polymer and a preparation method of the aluminum oxide ceramic precursor polymer. The preparation method of the aluminum oxide ceramic precursor polymer comprises the following steps: adding acetylacetone into a toluene solution of aluminum isopropoxide; carrying out a coordination reaction under a reflux state; adding water to carry out a controllable hydrolytic polycondensation reaction; finally, removing the solvent toluene to prepare the aluminum oxide ceramic precursor polymer. The aluminum oxide ceramic precursor polymer can be dissolved with a plurality of types of organic solvents to obtain a solution of the aluminum oxide ceramic precursor polymer, namely an aluminum oxide liquid-phase ceramic precursor; the solid content is adjusted so that the viscosity of the aluminum oxide liquid-phase ceramic precursor can be controlled to be 20mpa.s to 500mpa.s, and the manufacturability is good; the aluminum oxide liquid-phase ceramic precursor can be used as impregnated resin of a ceramic-based composite material through an impregnating-cracking composite material molding process; the aluminum oxide ceramic precursor polymer can also be used for preparing aluminum oxide ceramic fibers. Therefore, the disadvantage that a traditional inorganic method has poor manufacturability is overcome, and the compounding of a continuous fiber enhancing body and a base body is facilitated.