Abstract: Relationship formula between average concentration of harmful gas and pressure ventilation supply volume in refuge chamber was given, CO2 concentration distribution in refuge chamber under conditions of different pressure ventilation supply volume and air outlet layout were analyzed through refuge experiment with 50 people. The experimental results show that when air supply volume per person is 84 L/min, CO2 volume fraction in refuge chamber could be controlled under 1%; CO2 concentration distribution is uneven when only one air outlet is set in refuge chamber, air outlets should be evenly arranged in both sides of long passage of refuge chamber, and CO2 concentration distribution is more even with more air outlets.