The invention discloses a dual-energy X-ray phase-contrast imaging system without a stepping device and a realization method thereof. The system includes a dual-energy array X-ray source, a sample, aphase grating, a dual-energy analysis grating, and an X-ray detection device in order along an optical path, the dual-energy array X-ray source adjusts tube voltage to emit X-rays having different energies, and turns the X-rays into a series of individually coherent but mutually incoherent light; the phase grating separates the incident light into different diffraction orders, periodic interference fringes are formed at the dual-energy analysis grating, and moire fringes extraction phase information can be formed with the dual-energy analysis grating, and the X-ray detection device records moire fringe images. By adjusting the energy of X-rays, the dual-energy X-ray phase-contrast imaging system provided by the present invention utilizes the dual-energy analysis grating to convert different energy X-rays, and does not need to move the grating during imaging, the imaging steps are reduced, and the mechanical accuracy requirements are reduced.