Abstract: Based on the metro running tunnel section from Wawuzhuang station to Guizhou Road station of Qingdao metro line 1, a physical model of ventilation and exhaust system is built. In light of the fan combinations of option1 (Two forced fans + two exhaust fans), option 2 (Two forced fans + one exhaust fan on the left side of a smoke ceiling vent) and option 3 (Two forced fans + one exhaust fan on the right side of a smoke ceiling vent), an analysis is conducted and the input variable frequencies, power consumptions, air velocities and static pressures in the left and right carriageways are obtained under the three fan combination options. The experimental data show that the static pressure field in both carriageways are symmetrically distributed with the ceiling smoke vent as the symmetry axis,and characterized by an oscillating phenomenon, whether in option 1, option 2 or option 3. This oscillation exhibits an approximate constant of static pressures, and increase of consumed powers will hardly cause compensatory increase of air volumes, meanwhile it is also a key to evaluate the effects of fan combinations on relative shock loss when air flow passes through ceiling smoke vent. In order to quantify the difference of the shock loss (i.e. resistance),a concept of the performance coefficient of the ventilation and exhaust system, and a calculation model of deviation percentage is proposed, with the result of the resistance in option 1 being the smallest under the three combination modes. Thus it is recommended that the option 1 should be a preferential fan combination for an extra-long and large tunnel.