A hard X-ray grating phase-contrast imaging apparatus with large field-of-view, high contrast and low dose and the method thereof. The apparatus includes a source emitter (31), a source grating (G0), a beam splitting grating (G1), an analyzer grating (G2) and a detector (32) arranged in sequence on a transmission path of the source emitter (31). The beam splitting grating (G1) has a period of 30 to 50µm and a depth to width ratio not greater than 20. The apparatus can provide a high image contrast and a low radiation dose and realize a phase-contrast imaging with high energy and a large field-of-view by increasing the grating period, increasing a duty cycle of the beam splitting grating while increasing the distance between an object and the analyzer grating. The apparatus can also utilize the conventional polychromatic X-ray sources and available process for manufacturing gratings, and be suitable for clinical use.
