This paper established the three-dimensional model of the exhaust port of a diesel engine by reverse engineering technol-ogy.The steady state flow field in the three-dimensional model was numerically simulated by the use of CFD software FIRE.The steady state flow experiment of the exhaust port was carried out on the stationary flow test bench.The result shows that the simulation data in every lift of exhaust valve agrees well with the experiment data,and the method is useful to guide the design and optimization of exhaust port.