In order to reduce the tolerance of laser communication optical system, save the development cost, and reduce the influence of atmospheric scattering on laser communication link, the middle infrared laser with its wavelength working at the atmosphere window was used as the laser communication light source, and a matching middle infrared laser communication terminal optical system was developed. Firstly, based on the energy link transmission equation of laser communication, the design parameters of the optical antenna, such as aperture and divergence angle, were calculated according to the beam parameters of the middle infrared laser and the detector sensitivity of the receiving terminal, and the wave aberration requirements of the optical transmitting and receiving system of laser communication were given. Then, the design and tolerance analysis of the optical system for the middle infrared laser communication optical antenna were carried out by ZEMAX software, and the system was processed and adjusted to complete the development of the system, and the image quality of the two optical systems was tested. The test results show that the maximum deviation of transmitting optical system MTF from the theoretical value is 9.3%, and the wavefront aberration RMS of the receiving optical system is 0.075λ (λ=4.7 μm), which meets the design requirements. The results show that the difficulty of processing and adjusting optical antenna can be reduced by using the middle infrared laser as the laser communication light source.