A double liquid crystal adaptive optics closed loop system is characterized in that a natural light is divided into two mutually vertical polarized lights through a first 90-degree beam splitting polarizer, one is transmission polarized light P and directly corrected by a first liquid crystal wavefront corrector, after correction the polarized light P is modulated into polarized light S by a first1/2 wave plate; another is reflection polarized light S which is first modulated into polarized light P by the 1/2 wave plate and then corrected by a second liquid crystal wavefront corrector, aftercorrection, the polarized light S and the polarized light P are respectively reflected and transmitted by a second 90-degree beam splitting polarizer that is reversely used and then combined to outputa natural light, without polarized light intensity loss; on the premise of adding no cost of liquid crystal devices and causing no change to device structures, the invention adopts the liquid crystalwavefront correctors to match with a polarized beam splitting system and a polarized beam combining system, thus solving the defects of a low wavefront detection luminous energy utility rate and theincapability of working under dim light conditions caused by an adaptive optics closed loop system composed of liquid crystal devices.