Changxing, Huzhou, Zhejiang Province, is located in the Taihu Lake, where plains, rivers and ports are interwoven. In the past decade, a number of Steel Truss Bridges of various types have been built. In recent years, Steel Truss Bridges have been widely used because of their advantages such as less number of components, light weight and quick construction and assembly across waterways. With the increase of service life of Steel Truss Bridges, some of the members are aging and broken to different degrees, resulting in structural load-bearing capacity that cannot meet the operational safety requirements. In order to ensure the steel truss Bridges under the action of cyclic loading for a long time of operation safety and traffic flow, prolong the service life of bridge, reduce cycle maintenance cost, adopts unmanned aerial vehicle (UAV) remote sensing technology to inspect the structural appearance of a steel truss bridge in Changxing, and the research results found that the case bridge has typical diseases such as coating deterioration, steel corrosion and bolt fracture off. Based on the analysis of the causes of the steel bridge diseases, the preventive maintenance technology research is carried out, and the maintenance of the anticorrosive coating of steel members, the inspection and treatment of welds and cracks, the treatment of rod bending and damage, the preventive management and maintenance of expansion joints and collision barriers and other subsidiary structures are proposed to provide some reference for the management and maintenance of similar steel bridges.