Abstract: Based on the structure of a tunnel ventilation network and the principles of airflow in it, simulation computation is done for the ventilation of two long highway tunnels using the Scott- Hosley method and the ventilation path method to investigate the effects of the placement and adjustment of jet fans. The results show that a long tunnel with longitudinal and sectional ventilation forms a network and its computation can be carried out by natural airflow distribution to determine the site of jet fans, the amount of airflow and the mode of airflow regulation.