Abstract: In order to further tap into the energy saving potential of the ventilation and air-conditioning system in the public area of urban rail transit underground stations, and to solve the shortcomings of the conventional all-air system such as high energy consumption and large space occupied by pipes, a distributed air-conditioning system is applied in the project of Changsha Rail Transit Line 6. Through technical and economical comparison and analysis of applying two different ventilation and air-conditioning scheme, all-air system and distributed air-conditioning system, in underground station public area, conclusion is arrived to as follows: compared with all-air system, distributed air-conditioning system has relatively less investment in equipment, similar in civil engineering, and less in operating cost. From the perspective of reducing fan power consumption and serving terminal control, distributed air-conditioning system has more advantages.