Abstract: Research status of evaluation method of mine ventilation system was summarized. In view of problem that existing evaluation methods were only for entire mine and unable to show ventilation condition of working face, an evaluation index system of ventilation effect of working face with high volume fraction gas was proposed. Eight evaluation indexes were gotten which could influence ventilation effect of working face directly according to investigation, including wind speed of working face, temperature of working face, humidity of working face, dust concentration of working face, ratio of supply to demand of wind volume, volume fraction of gas of working face, volume fraction of gas of top corner and volume fraction of gas of return airway. Scope of each evaluation index was given and membership function of each evaluation index was established. The system has been applied in W1301 working face of Sihe Coal Mine for evaluating ventilation effect with a result verifying rationality of the system.