Abstract: Ventilation system is an important part of the underground mine，and its comprehensive safety evaluation is of great significance in the production practice.Based on the related document，factors affecting the mine ventilation system are summarized as six indexes：qualified rate of air volume (wind speed)，qualified rate of air sources and quality，qualified rate of air quality in underground working environment，the available airflow rate of mine，efficiency of the main fan and air volume index of supply and demand.On this basis，the extension model of ventilation system evaluation is set up，and then the weights are integrated by game theory which be calculated respectively in advance by the variation coefficient method and the analytic hierarchy process.The integrated weight is used for evaluating the ventilation system.Finally，this model has been verified combining with the present situation of a mine ventilation system.The conclusion is that the safety of the mine ventilation system evaluation grade is medium (D₃)，and the comprehensive evaluation result is coincided with the actual situation

Key words: Mine ventilation system, Extension model, Variation coefficient method, AHP, Game theory