The invention relates to a method for preparing tricalcium aluminate by the aid of spark plasma sintering techniques. The method includes analyzing raw materials which are pure calcium carbonate CaCO3 and pure gamma-phase aluminum oxide gamma-Al2O3; carrying out ball-milling on the pure calcium carbonate and the pure gamma-phase aluminum oxide and then controlling the heating rates and the cooling rate of a spark plasma sintering furnace under the conditions of vacuum degrees of (30-50) Pa, pulse ratios (ON/OFF) of (6/1-48/8) and axial pressures of (1-3) kN; fetching samples out of the spark plasma sintering furnace when the temperatures of the samples are reduced and reach (60-90) DEG C and grinding the samples to obtain particles with the sizes smaller than 20 micrometers so as to obtain the tricalcium aluminate. The method is simple and convenient, and the synthesis efficiency is improved by (10-20) times as compared with the traditional method. The method has the advantages of speediness, high efficiency and energy conservation.