Abstract: SNCR, SCR, LoTOx or combined technologies were commonly used in circulating fluidized bed（CFB） boiler to control the NO_x emission for meeting the policy requirements. Nevertheless, introduction of those complicated equipments would bring extra expensive costs for production. In order to reduce the denitrification cost of CFB boiler systems, in-situ denitrification catalysts were designed and prepared based on the mechanism of the formation evolution of nitrogen compounds in CFB furnace. Denitration activity of the catalysts were measured within laboratory and industrial experiments. Denitration activity of the catalyst reached about 99% in fixed bed reactor condition, 63.1%−78.1% in medium scale CFB combustor, and the anti-sintering of the catalyst was also proved excellent during the experiments. In the industrial application, the NO_x concentration in the exhaust gas decreased more than 60% by 5% addition of the catalysts to the bed material, meanwhile leading a higher fuel efficiency of the conbustion process. Development of the in-situ denitrification technology provides not only higher operation flexibility of the CFB boiler system, but also an alternative economical and practical option for its denitration process.