In ground-based astronomy,light from distant objects is distorted by the atmosphere turbulence as it propagates to the earth.This leads to severe degradation in the image quality of a telescope.The purpose of adaptive optics(AO)systems is to physically compensate for the distortion,thereby greatly improving the image quality.However,AO systems with a deformable mirror corrector are now used at most current generation of large telescopes,are limited by its actuators number to be used in visible light telescope with aperture larger than 4m,because it is too difficult to finely machining so many actuators.On the contrary,liquid crystal(LC)phase modulators have millions of driving pixels,large phase stroke,non-mechanical movement and low cost.Therefore,the LCAO system is promising to be used for telescopes with diameter of 4m to 10m.