Disclosed are a method for preparing a catalyst, which has excellent nitrogen oxide-removal performance and resistance over a wide temperature range, and the use of the catalyst. According to the disclosed method, the oxidation number and surface defects of the catalyst are changed by applying artificial high energy through mechanical ball milling during the preparation process of the catalyst, instead of applying the addition of a precious metal, the deformation of a support and the use of a co-catalyst in order to increase NOx removal activity, such that activation energy for inducing redox reactions can be decreased.