With ICEM software, the mesh generation of the two-dimensional cross-section of the simplified gas flow channel of excimer laser is introduced. Based on realizable k-ε model and multiple reference frame (MRF) model, the simulation to the steady-state flow field of gas flowing inside laser with FLUENT software, and the velocity value and its distribution of gas flow are obtained. The simulation results indicate that there exist linear relationships between the average gas flow velocity and the rotational speed of blowers, also between the torsional moment and the square of rotational speed of blowers. The gas flow velocity distribution measured by a pitot tube is compared with the simulation results, and the consistency between them confirms the validity of the latter.