Abstract: Emission optical system plays an important role in improving performance of surface layer UV communication system. UV communication emission optical system in surface layer is designed. Through analysis and comparison, this system adopts Cassegrain structure. Its main mirror is paraboloid and secondary mirror is hyperboloid, working at wavelength 265 nm~270 nm and ambient temperature -60 ℃~ 60 ℃. After optimization design, results are as followings: system focal length is 450 mm, total length of system is 200 mm, emission angle is 2°, MTF value is greater than 0.31, and working temperature is stable.