The disclosed technology relates to a ray energy calibration device and method, and a ray imaging system. In one aspect, the ray energy calibration device includes a plurality of wheels arranged to be rotatable about a common shaft and each provided with one or more protruding blocks at respective specific positions of an outer circumference thereof. The ray energy calibration device further includes a plurality of calibration members, with each of the calibration members being configured such that through rotation of a corresponding one of the wheels, the calibration member can be moved to a calibration position by the protruding block at a specific position on the outer circumference of the wheel.