Four different air distribution models are designed on basis of positions of ventilation holes and variation of air volume of lower ventilation holes, so as to rationally design the air distribution in gas fire extinguishing room of a Metro station in Shenyang. The air distribution is simulated by means of CFD technology. The velocity field and temperature field are analyzed. The author does not regard the lower ventilation hole as a best choice. An electric air volume adjusting button setting on ventilation pile is proposed. Points to which attention should be paid in air distribution design in gas fire extinguishing room of Metro stations are presented. The paper can provide guidance for the design of other projects.