With the development of navigation and communication technologies, the unmanned aerial vehicle (UAV) has become one of the popular platforms for aerial mapping. UAV is a generic aircraft designed to operate with remote control or autonomous flight, but without a human pilot aboard. For disaster surveillance, UAV provides excellent maneuverability and easily tasks disaster surveying for specific hazardous locations where road closures and blocks may occur due to landslides or other disaster events. Using UAV not only shortens relief time, but also ensures the safety of personnel. In this paper, a case study of Kaohsiung Gas Explosion event on July 31, 2014 was used to illustrate the applications of disaster surveillance using UAVs. The operating procedure and the image process with UAV in this event are introduced in detail.