A method for removing a ceramic mold core of a hollow blade of an aeroengine comprises the three steps of primary core-removing, secondary core-removing and acid liquid neutralizing and cleaning, wherein the concentration of KOH alkaline liquid used for core-removing is 30%-40%, the temperature of the alkaline liquid for core-removing of each time is 150 DEG C, the core-removing pressure is 0.2-0.7 MPa, and the core-removing time of each time is 20 h. According to the method, the method that the concentration of the alkaline liquid is decreased, pressurizing and depressurizing are conducted atintervals in the process is adopted, so that the alkaline liquid is boiled and makes full contact with the mold core, thus, the scouring action is achieved, and the full core-removing effect is achieved; and the temperature of the alkaline liquid is increased by increasing the pressure instead of increasing the concentration of the KOH alkaline liquid, therefore, core-removing is facilitated, corrosion to a casting can be relieved, the core-removing time is shortened to two days, and the qualification rate of one-time core-removing reaches 98% or above.