The present invention relates to multi-energy CT imaging system and imaging method. The multi-energy CT imaging system comprises: a stage for carrying the object to be inspected； voltage-regulatable X-ray generation device for emitting X-rays； a detector for receiving X-rays emitted from said X-ray generation device and penetrating said object to be inspected, and for outputting detection data； a rack having said X-ray generation device and said detector mounted thereon； and a data processing and control device for controlling said stage, said X-ray generation device, said detector and said rack, processing detected data, and during one rotation of scan of said X-ray generation device, evenly dividing the circular track of said X-ray generation device into angle intervals of a predetermined number according to the predetermined number of energies and setting a different high voltage of said X-ray generation device for each angle interval, and when said rack rotates from the current angle interval into a next angle interval, controlling said X-ray generation device to switch it to a voltage set in the next angle interval.
