The application relates to a system and a method for the phase-contrast imaging by use of X-ray gratings. The system comprises an X-ray device, a first absorption grating, a second absorption grating, a detection unit, a data processing unit and an imaging unit, wherein the X-ray device transmits an X-ray bundle to a detected object the first and second absorption gratings are positioned in the direction of the X-ray bundle the X-ray refracted by the detected object forms an X-ray signal with variable intensity through the first absorption grating and/or the second absorption grating the detection unit receives and converts the X-ray with variable intensity into an electrical signal the data processing unit processes and extracts refraction-angle information in the electrical signal, and utilizes the refraction-angle information to figure out pixel information and the imaging unit constructs images of the object. In addition, the system and the method can also realize CT imaging by using a rotating structure to rotate the object so as to obtain refraction angles in a plurality of projection directions and the corresponding images, and use CT reconstruction algorithm to figureout refraction-index fault images of the detected object. According to the invention, the phase-contrast imaging of approximate decimeter-magnitude viewing fields under incoherent conditions can be realized by use of common X-ray machines or multi-seam collimator such as source gratings, as well as two absorption gratings.
