The invention relates to a system and a method for X-ray grating contrast imaging. The system comprises an X-ray launching device, a first absorption grating, a second absorption, a detecting unit, a data processing unit and an imaging unit, wherein the X-ray launching device is used for launching X-ray beams to a detected article; the first absorption grating and the second absorption grating arepositioned in the launching direction of the X-ray beams, and the X-ray refracted by the detected article forms X-ray signals with different intensity by the first absorption grating and the second absorption grating; the detecting unit is used for receiving the X-ray signals with changeable intensity and converting the X-ray signals into electric signals; and the data processing unit is used forprocessing and extracting the refraction angle information in the electric signals and calculating the pixel information through the refraction angle information; the imaging unit is used for constructing the image of the article. In addition, a rotating structure can also be utilized to rotate the article to realize a CT imaging mode so as to obtain refraction angles in a plurality of projectiondirections and the corresponding images and calculate the refraction index tomography image of the detected article by CT reconstruction algorithm. The system and the method adopt the common X-ray machine and the grating above a period of ten micron magnitude to realize the contrast imaging of a decimeter magnitude like viewing field.