Abstract: Provided is a beam irradiation system and a control method thereof. The beam irradiation system includes: a first irradiation chamber and a second irradiation chamber; a beam generation device to generate a beam and emit the beam to the first or second irradiation chambers; a system control module including a first control sub-module capable of controlling the beam generation device to emit the beam to the first irradiation chamber, and a second control sub-module capable of controlling the beam generation device to emit the beam to the second irradiation chamber; and a beam control module connected between the beam generation device and the system control module. For the first and second control sub-modules, one is capable of controlling the beam generation device through the beam control module when the beam control module is not occupied by the other, such that the same beam irradiation system controls multiple irradiation chambers respectively.