针对自由空间光通信技术的不断发展，及其在军用、民用领域的应用前景。在与传统的有线通信系统、无线电波通信系统相比较的基础上，阐述了近地面自由空间光通信系统的组成及其技术经济特点，分别深入分析了近地面红外与紫外这两种自由空间光通信系统的组成、工作原理和主要技术特点，提出了相应的主要性能指标与关键技术，并对这两种光通信的特点进行了较全面地比较研究。对于近地面自由空间光通信技术的进一步研究、工程应用与发展具有重要的作用和现实意义。

In light of constant development of free space optical communications and application prospect in the military and civilian fields, and on the basis of comparison between traditional wired networks and radio wave communication systems, this paper describes the composition of near ground free space optical communication system and economical and technological characteristics, and analyzes in detail the composition, working principle and main technological characteristic of infrared and the ultraviolet free space optical communication systems. Then the corresponding major performance indicators and the key technology are presented，thus a comparative study on the characteristics of these two free space optical communication systems comprehensively is made. It has important role in and practical significance for further research and engineering application and development of the free space optical communication.