In order to verify the validity of liquid crystal adaptive optics with a 600 mm telescope, Zemax software is used to design the liquid crystal adaptive optical system. The design demands are given according to the parameters of telescope, the turbulence and the liquid crystal. The optical system is designed with the above demands with Zemax software, and the characteristic of the system is evaluated. The focal length of the whole optical system is 35 m and the F number is 58. The limited line resolution at the image plane is 44.8 μm. It satisfies the sampling theorem because the size of the imaging CCD is 16 μm. Designed modulation tranfer function (MTF) of the liquid crystal adaptive optical system is almost the same as the diffraction limited MTF. Optical path difference (OPD) aberration of the system is about 0.1λ. The results show that the adaptive optical system has better optical characteristics.