Abstract: At first，the traditional method of simulated anneal is improved.Secondly，a zero-order term is effectively eliminated for hologram of pure phase by using independent component analysis，which receives a twin-image and phase unwrapping of a twin-image.Finally，the phase retrieval is achieved for phase unwrapping of a twin-image by using improved method of simulated anneal.Experiments show that this method can better resolve problem of a zero-order term and retrieval of phase in the process of the reconstruction of digital holography.