The serious disturb caused by atmosphere turbulence can be eliminated effectively and the astronomical image reconstruction with the diffraction-limited resoluiton of the telescope can be achieved by the spectrum masking. The key problem is to recover Fourier phase spectrum. Some actual problems that will be faced when to recover object phase spectrum from the bispctrum with a micro-computer are discussed, including the huge information of the bispectrum contradict the limited storage space of the micro-computer; the area and the path of phase recurring; phase wrapping and error accumulating in phase retrieving from the bispectrum. The corresponding methods used to solve these problems and the experimental result of image reconstruction for astronomical objects are given respectivly.