The present disclosure relates to a multi-spectrum X-ray grating-based imaging system and imaging method. In one illustrative implementation, an exemplary multi-spectrum X-ray grating-based imaging system according to the present disclosure may comprise an incoherent X-ray source for emitting X-rays to irradiate an object to be detected, a grating module comprising a first absorption grating and a second absorption grating which are disposed in parallel to each other and are sequentially arranged in an X-ray propagation direction, and an energy-resolved detecting device for receiving the X-rays that have passed through the first absorption grating and the second absorption grating.