Due to the air volume of branch of ventilation network is influenced by each other, and the method of change branch wind resistance to airflow distribution will be caused the air volume of decreased faster branch airflow cannot meet the minimum requirements, the air volume dispatchable model was set up based on airflow condition theory, an adjustment method of air volume based on air volume dispatchable model was proposed. The adjustment method uses ventilation network solution to calculate adjustable range of branch wind resistance, and obtains the air volume of branch from quantitative angle. Using the method to calculate air volume is convenient to choose the most adjustable branch and confirm the wind resistance adjustment range and variation of air quantity.