A multi-energy static security CT system comprises at least one N-stage image chain structure (5) and a baggage conveying belt (4) provided at an inner side at the bottom of the N-stage image chain structure (5). The N-stage image chain structure (5) and the baggage conveying belt (4) are fixed at a pre-configured positions by means of a machine frame (8). The N-stage image chain structures (5) are sequentially arranged in a forward direction of a baggage channel, and adjacent N-stage image chain structures (5) are offset relative to each other. By exposing radiation sources in the N-stage image chain structure (5) at different times, the static security CT system generates an image having a higher temporal resolution and more energy spectrum levels than an image generated by a spiral CT system. Also provided is an imaging method implemented by means of the static security CT system.