In order to investigate the characteristic of the flow field at the entrance of the nozzle bank in a chemical laser, a physical and numerical model which is compatible with the flow was established. The model based on experimental equipment contained two types of nozzle bank with three nozzles and four nozzles, respectively. The two-dimensional viscous conservation element and solution element (CE/SE) method was used to calculate the numerical model. The results show that the CE/SE method can simulate the flow process of the high temperature burned gas effectively. The parameters gained from the simulation accord with the experimental data as the flow reaches stable. To a single nozzle, the related parameters(such as pressure and velocity) distribution in the flow field is symmetrical, which can be extended to the nozzle bank with more nozzles.