A method for preparing an SCR catalyst may include: (1) placing a first aqueous solution containing a titanium oxide and a tungstate in an electric field environment, adjusting the pH value of the first aqueous solution, and adjusting the current direction of the electric field environment to obtain a first mixture; (2) providing a second mixture by, in the electric field environment, adding dropwise a second aqueous solution containing a soluble salt of one or more active components, a copper-organic polyamine complex and a dispersant to the first mixture, and adjusting the current direction; and (3) processing the second mixture to obtain the SCR catalyst. The one or more active components may be selected from Ce, Zr, Cu, Fe, Pr and Sc.