Abstract: The performance of the denitration catalyst could affect the efficiency and operation behavior of SCR system directly. In this paper, the exterior appearance as well as the physicochemical and operational characteristics of the denitration catalyst are tested after 28 000-h operation in a coal-fired power plant. The results show that the overall performance of the catalyst is well maintained, but the ratio of its activity to that of fresh one i.e. K/K₀ is lower than the threshold value of the lifespan. In order to satisfy the NO_x discharge up to the standard, the catalyst should be replaced or regenerated in time. Based on these test results, the suggestions on the denitration system optimization and economic operation are proposed.