Numerical modeling of a front wall pulverised coal fired utility boiler is presented in this paper. Comparison between the pre-dictions and measurements in the boiler is addressed. The accordance of the calculation results with the experimental data at several operating conditions validates the models and algorithm employed in the computation. The need to improve burner or boiler design with the objective of producing Nox abatement while avoiding some negative side effects is also the motivation for the prediction of furnace performance for different boiler operating conditions. The predicted results also lay a foundation for the boiler operating expert system