The gas flow verification system with positive pressure sonic nozzle has high requirements for the stability of air source pressure. It is difficult to control the stagnation chamber pressure within the set value range, and adopt the dynamic characteristic analysis based on the mechanism model. To solve the aforementioned problems, a modeling and parameter identification method is proposed by using data and the mechanism model for the gas flow verification system with positive pressure. Aiming at the nonlinear dynamic parameters in the process of mechanism modeling, the stochastic configuration network is used for dynamic parameter identification. The RMSE of the pressure and temperature in the stagnation cabin after identification and the actual data are 1. 26×10 4 and 2. 64× 10 -4 , respectively. In view of the dead zone of the control valve or the replacement of the control valve in the actual operation, the disturbance experimental analysis of the model is carried out. The practical results show that the dynamic mathematical model reflects the change trend of pressure in the pressure regulation link, and has a certain practical application value.