Abstract: A big data environment is formed in road traffic system. In order to clarify the research contents, key technologies and technical solutions of the road traffic big data, the connotation, features and research status of big data are summarized. Secondly, from the view of people, vehicles, roads and the environment, the data sources of road traffic big data are analyzed. Then, from the view of traffic information acquisition, transmission, processing and application, the key issues of road traffic big data are analyzed. Finally, from the perspective of data processing and management, the key technologies of road traffic big data processing and management are analyzed. Through the above analysis, the future applications of road traffic big data key issues, main technologies and technical basis for the road traffic big data are presented. The study of road traffic big data attempts to provide a technical guidance and related applications.