An X-ray imaging system comprising: an X-ray source, a source grating, a fixed grating module and an X-ray detector, which are successively positioned in the propagation direction of X-ray an object to be detected is positioned between the source grating and the fixed gating module said source grating can perform stepping movement in a direction perpendicular to the optical path and grating stripes wherein the system further comprises a computer workstation for controlling said X-ray source, source grating and X-ray detector so as to perform the following processes: the source grating performs stepping movement in at least one period thereof at each stepping step, the X-ray source emits X-ray to the object to be detected, and the detector receives the X-ray at the same time wherein after at least one period of stepping and data acquisition, the light intensity of X-ray at each pixel point on the detector is represented as a light intensity curve the light intensity curve at each pixel point on the detector is compared with a light intensity curve in the absence of the object to be detected, a pixel value of each pixel point is calculated from change in said light intensity curve an image of the detected object is reconstructed according to the calculated pixel value.
