The invention discloses an air-conditioner unit used for an emergency four-constancy air-conditioning system of a high-speed train. The air-conditioner unit used for the emergency four-constancy air-conditioning system of the high-speed train comprises an air conditioner unit body, a buffering device and an emergency case. Pin holes are formed in the buffering device. The buffering device is mounted on the back side face of the air-conditioner unit body through matching of fixing pins and the pin holes. The emergency case is arranged on the lower portion of the air-conditioner unit body. An emergency power supply and an emergency power supply judgment device are arranged inside the emergency case. One end of the emergency power supply is connected with a power grid of the air-conditioner unit body, and the other end of the emergency power supply is connected with the emergency power supply judgment device. By adoption of the air-conditioner unit used for the emergency four-constancy air-conditioning system of the high-speed train, the phenomena that after an outage happens to the high-speed train due to an emergency accident, the air-conditioning system stops operating, the oxygen concentration in a cabin is decreased, the temperature is increased, and the air is dry are avoided; and the air pressure in the cabin of the high-speed train is guaranteed, oxygen is sufficient, the air is clean, and the temperature and the humidity are moderate, and life safety of passengers on the train is guaranteed more effectively.