The invention provides a cerium-tungsten-tantalum denitration catalyst. In the catalyst, the molar ratio of cerium to tungsten to tantalum is 2-5:1-4:1-4. A preparation method of the cerium-tungsten-tantalum denitration catalyst comprises the following steps: (1) firstly, mixing and dissolving a cerium source and a tungsten source in water, and then adding a tantalum source to obtain a mixed solution; (2) adjusting the pH of the mixed solution obtained in step (1) by using a weak base solution, so that the pH value reaches 9-11; (3) sequentially filtering, drying and grinding the mixed solution obtained in step (2) to prepare an active component; (4) mixing the active component obtained in step (3) with carrier powder, an assistant and water and uniformly mixing to obtain a paste stock; (5) performing extrusion molding on the paste stock obtained in step (4) to obtain a molding catalyst; (6) drying the molding catalyst obtained in step (5) to obtain a dried molding catalyst; and (7) calcining the dried molding catalyst obtained in step (6) to obtain the cerium-tungsten-tantalum denitration catalyst. The denitration catalyst prepared according to the invention is nonhazardous, highin activity and long in service life.