According to the requirement to the coherent laser radar, a coherent laser radar antenna system was simplified by using a binary optics element with planar substrate to correct aberration. Only one large aperture spherical lens and one small aperture spherical lens as well as one small aperture binary optical corrector with planar substrate were used in the system. The designing parameters are, as a transmitting system, the objective field of view 2ω=10°, the aperture of the exit pupil Φ=100 mm, the reducing times of the angle of the diverging beam β=5×, the wavelength of the laser source λ=10.6 μm. The designing result is that the imaging quality of the optical antenna system reaches the diffraction limit.