The utility model relates to a multi-energy CT imaging system comprising an objective table, a voltage-adjustable X-ray generating device, a detector, a rack and a data processing and control device. The objective table is used for placing a detected object the X-ray generating device is used for emitting an X ray the detector receives the X ray emitted from the X-ray generating device and passing through the detected object and outputs detection data the rack is used for assembling the X-ray generating device and the detector and the data processing and control device is used for controlling the objective table, the X-ray generating device, the detector and the rack, processing the detection data, equally dividing a circular track of the X-ray generating device into a predetermined number of angle intervals according to the predetermined number of energies during one-circle scanning process of the X-ray generating device, setting a different high voltage of the X-ray generating device for each angle interval, and controlling the X-ray generating device and switching the voltage of the X-ray generating device into the voltage set for a next angle interval when the rack rotates from a current angle interval to the next angle interval.
