A new computational fluid dynamics (CFD) method for the simulation of fast-axial-flow CO[EQUATION] laser is developed. The model which is solved by CFD software uses a set of dynamic differential equations to describe the dynamic process in one discharge tube. The velocity, temperature, pressure and turbulence energy distributions in discharge passage are presented. There is a good agreement between the theoretical prediction and the experimental results. This result indicates that the parameters of the laser have significant effect on the flow distribution in the discharge passage. It is helpful to optimize the output of high power CO[EQUATION] laser by mastering its kinetic characteristics.