The invention provides a denitration catalyst and a preparation method thereof, and a
waste gas denitration method, belonging to the field of
waste gas treatment. The denitration catalyst comprises a core layer, a middle layer and a shell layer, wherein the core layer comprises
titanium nanotubes, the middle layer comprises
manganese oxide, and the shell layer comprises
iron oxide. The preparation method of the denitration catalyst comprises the following steps: subjecting a
manganese oxide precursor to reacting with the
titanium nanotubes to obtain the
titanium nanotubes loaded with the
manganese oxide, and then modifying the titanium nanotubes loaded with the
manganese oxide by using an
iron source to obtain the denitration catalyst. According to the
waste gas denitration method, waste gas denitration is carried out by using the denitration catalyst. The denitration catalyst provided by the invention has higher stability, activity, selectivity and
sulfur resistance; raw materials used in the preparation method are environment-friendly and easily available, operation is simple and controllable, and expanded production is facilitated; and when the denitration catalyst is used for denitration treatment of waste gas, a denitration rate is high, selectivity is good, and stability is high.