The invention discloses a preparation method of a medium-low-temperature smoke SCR catalyst. The preparation method comprises the following steps: (1) completely dissolving a titanium precursor, a cerium precursor, an active metal salt and a chelating agent in a solvent, and recording as a solution A; recording a mixed solution of water and ethanol as a solution B; (2) slowly dropwise adding the solution B into the solution A to obtain a mixed solution; (3) adding a drying agent and accelerant into the mixed solution obtained in the step (2); (4) aging the mixed solution obtained in the step (3) to form gel-shaped solids; (5) washing the gel-shaped solids obtained in the step (4), and soaking; and (6) drying and roasting the solids obtained in the step (5) to obtain a denitration catalyst. The method is moderate in reaction conditions and simple in process; and the prepared catalyst is large in specific surface area, higher in oxidization reduction capacity and surface acidity, excellent in denitration activity and heat stability in a range of 150 to 400 DEG C, and high in water resistance and SO2 toxicity resistance.