With the development of economy in China and the improvement of social life, the national general aviation industry is rising step by step. Low-altitude airspace is also gradually opening up. At the same time, the opening of low-altitude airspace has further promoted the development of the aviation industry. Some new low-altitude aircraft have been put into use. The increase in the number of low-altitude aircraft has resulted in frequent safety accidents in low-altitude airspace. In order to settle with the security issues in low-altitude airspace, we need to build a healthy low-altitude airspace surveillance system. This paper firstly analyzes the current situation of low altitude airspace security. Secondly, it introduces the basic situation of the ADS-B technology. Thirdly it introduces the functional module of the ADS-B system. Then it expounds the application and trend of ADS-B technology in airspace, and discusses the existing problems this technology and possible solutions. Finally, it elaborates the future development and prospects of ADS-B technology in low-altitude airspace security.