Abstract: To solve the problem existing in a certain coal-fired thermal power plant that its SCR denitrification system was unable to keep long-term stable NO_x emission after near-zero emission retrofit, an investigation was conducted on the thermal control logic, and subsequently key thermal control technologies were proposed for the SCR denitrification system, which were then put into engineering application. Results show that the average NO_x concentration of unit could be reduced to below 200 mg/m³ through optimization on the generation process of NO_x; effective deviation adjustment could be fulfilled by introducing intelligent predictive feedforward control to the original feedforward-feedback cascade control; the emission concentration of NO_x from the funnel could be reduced to below 50 mg/m³.