A vehicle comprising an air conditioning system comprising: an air-conditioning case having a cold air passageway and a warm air passageway which is disposed above the cold air passageway; the cold and warm air passageways (111 and 112) are arranged in a structure that is stacked up and down in the air-conditioning case; a division wall partitioning the cold air passageway and the warm air passageway is formed inside the air-conditioning case; the cold air passageway is disposed below the division wall and the warm air passageway is disposed above the division wall; and a distribution duct, which is connected with an outlet of the air-conditioning case and includes a defrost vent, a face vent, and a floor vent disposed to distribute cold air and warm air discharged from the air-conditioning case to a specific position of the interior of the vehicle according to air discharge modes, characterized in that the air-conditioning case is arranged at the side of an engine room relative to a dash panel, which partitions the engine room from the interior of the vehicle, and the distribution duct is arranged in the interior of the vehicle, the floor vent is formed adjacent to the dash panel in the distribution duct, and the defrost vent and the face vent are partitioned from each other at an upper part of the distribution duct, and the floor vent is formed between an air inflow port of the distribution duct and the defrost vent. an air-conditioning case having a cold air passageway and a warm air passageway which is disposed above the cold air passageway; the cold and warm air passageways (111 and 112) are arranged in a structure that is stacked up and down in the air-conditioning case; a division wall partitioning the cold air passageway and the warm air passageway is formed inside the air-conditioning case; the cold air passageway is disposed below the division wall and the warm air passageway is disposed above the division wall; and the cold and warm air passageways (111 and 112) are arranged in a structure that is stacked up and down in the air-conditioning case; a division wall partitioning the cold air passageway and the warm air passageway is formed inside the air-conditioning case; the cold air passageway is disposed below the division wall and the warm air passageway is disposed above the division wall; and a distribution duct, which is connected with an outlet of the air-conditioning case and includes a defrost vent, a face vent, and a floor vent disposed to distribute cold air and warm air discharged from the air-conditioning case to a specific position of the interior of the vehicle according to air discharge modes, characterized in that the air-conditioning case is arranged at the side of an engine room relative to a dash panel, which partitions the engine room from the interior of the vehicle, and the distribution duct is arranged in the interior of the vehicle, the floor vent is formed adjacent to the dash panel in the distribution duct, and the defrost vent and the face vent are partitioned from each other at an upper part of the distribution duct, and the floor vent is formed between an air inflow port of the distribution duct and the defrost vent.