The invention discloses a radiation refrigeration air conditioner with a dehumidification system. The air conditioner comprises an air conditioning refrigeration device and a radiation refrigeration device; a refrigerant outlet of the air conditioning refrigeration device is connected with one end of the radiation refrigeration device through a refrigerant outflow main pipeline, and a refrigerantinlet of the air conditioning refrigeration device is connected with the other end of the radiation refrigeration device through a refrigerant inflow main pipeline; the air conditioner further comprises the dehumidification system, and the dehumidification system consists of an air flow guide part and a surface cooler; the air flow guide part is a magnetic coupling fan, the magnetic coupling fan comprises a magnetic coupling power mechanism and a fan, a power input end of the magnetic coupling power mechanism is used for collecting the refrigerant flowing kinetic energy in the refrigerant outflow main pipeline, and the magnetic coupling power mechanism is used for transmitting the refrigerant kinetic energy to the fan to drive the fan to rotate; and the surface cooler comprises a condensation coil pipe and a liquid collector, the condensation coil pipe is arranged on the air outlet surface of the magnetic coupling fan, and the liquid collector is connected to the condensation coil pipe. According to the air conditioner, an inner surrounding structure of a building can be effectively prevented from generating condensation.