In order to solve the serious secondary disasters of the gas overrun or gas explosion,which is caused by coal and gas outburst in mine,the equations of fluid transients,convection diffusion and source-containing ventilation net- work were established to study the dynamic effect and gas migration process of gas outburst in mine ventilation system. In this paper,the gas migration process under the combined effect of gas outburst power and mine ventilation was in- vestigated through the outburst dynamic experiment of ventilation network system. A simulation software NC2. 0 of coal and gas outburst has been developed,and the “10·27” coal and gas outburst accident in Jiaozuo Jiulishan Coal Mine was simulated by NC2. 0 software. Throughout the simulation process,the unsteady air flow and gas distribution in Jiul- ishan Coal Mine after gas outburst were simulated respectively by the fluid changing curve given. The results indicate that the outburst pressure after gas outburst is the main factor leading to airflow change,propagating by wave propaga- tion. The high strength airflow changes the direction of air flow,increases the air volume in return airway,and decrea- ses the air volume in intake airflow roadway at the same time,even leading to backflow. The research provides a theo- retical basis for disaster prevention and control,reducing loss and preventing secondary disasters in outburst mines.