With the development of aerospace technology, modern small satellite has gradually become lighter, smaller, lower cost. The small satellite has become an important part of the space system, which has advantages of high density and costeffective. In the military application field, the small satellite has played a huge role in improving the strategic deterrent effect of space system, satisfying the demands of battlefield strength enhancement, fulfilling the requirement of battle force and pushing the strategy of technological development of space confrontation, and facilitating the realistic demand of new technology demonstration and verification. Firstly, the definition and development of small satellite are summarized. Based on the typical foreign small satellite projects, the application of small satellite in battlefield situational awareness, military communication, spacebased surveillance system, space confrontation and other fields are analyzed. Finally, based on the shortcomings of our military development of small satellite project, suggestions for the development of small satellites in our military are provided, which can provide reference for China to carry out space research based on microsatellite.