Phase Diversity (PD) method estimates both the wave-front phase and object by two focused and defocused images with known phase as the prior information. An image restoration experiment by using PD method was designed. The wave-front phase aberration caused by atmosphere turbulence was simulated by using the deformable-mirror. Due to simplifying the optical system and eliminating the effect of chromatic aberration，the Offner reflector was used to design the reflective imaging system. Experiment results indicate that, compared with the origin image, the resolution of the restored image can increase by 12% and the ability of improving image resolution and phase estimation is verified. So the proposed method can be used as a good means to restore the degradative images in the large aperture telescope.