For cement plants, great attention is being given to the emission of the pollutant gases, especially NO. Because of the increasingly stringent emission constraints at cement plants, it is becoming more important to predict emissions accurately and then decrease the release quantity. The precalciner is an important apparatus in the cement production process, in that it can reduce not only the heat loading of the rotary kiln but also the NO emission, because of its relative low operating temperature. In this paper, the NO release was simulated based on the full-scale modeling for the precalciner and the model results were compared with measurements to validate the simulation models. The optimum cases of air staging and fuel staging were analyzed by executing a simulation technique on the restructuring precalciner with no effect on the operation process, and the conclusion is that the fuel staging case is the optimum method economically.