Abstract: The technical transformation schemes and effects of ultra-low emission for the cement rotary kiln were introduced from stability the quality of raw materials and fuel, upgrade and maintenance of the equipment, technology of optimized grading combustion, application of high efficiency and intelligent denitration system, etc. Since May 2021, the kiln system has been operating stably. The initial value of NOX has been successfully reduced to 820mg/Nm3, the NOX emission has been controlled at lower than 50mg/Nm3, and the total daily discharge of pollutants is controlled at 612kg/d. The average usage of ammonia is 0.6~1.0m3/h and the concentration of ammonia escape is controlled less than 8mg/Nm3.