A computer simulation code for an electron-beam-excited XeF(B → X) laser using Ar/Xe/F2 mixtures was constructed on a point source model and solves rate equations for twenty-six species and gas electron temperatures by a Runge-Kutta method. These equations include about 150 reactions. Experiments were carried out for a gas mixture of 93.2% Ar, 6.0% Xe, and 0.8% F2. Calculations at room temperature and low pressure (< 1atm) show good agreement with experimental results. A high intrinsic efficiency of approximately 3% is obtained at an excitation rate of 0.5-2.0 MW/cm3-atm. This result is attributed to the reduced formation of absorption species.