Civil unmanned aircraft system (UAS) traffic management is the core of UAS operation management. At present, most of the researches on UAS traffic management(UTM) are in the stage of strategy making and discussing and demonstrating the key supporting technology scheme of a single operational scenario. There is no systematic disclosure of civil UTM framework and technology trends. Based on the analysis of the current situation of foreign civil UAS traffic management, the system framework of civil UTM adapted to all the UAS operational scenarios was designed. It specified UAS operation scenarios, management strategies, UTM ecosystem. In order to support the implementation of the civil UTM system framework, 11 civil UTM key technologies were proposed for delicacy management of airspace, operational safety and separation management, traffic guidance and control, intelligent facility planning and application. And the status quo of key technology development was analyzed and the development direction of key technology was summarized. The research shows that civil UAS traffic management should adapt the hierarchical classification management strategies which is the oriented to operational scenarios and risk-based, and serve the sustainable development needs of UTM ecosystem. In terms of UTM technologies, it may take multi-scenario, multi-type, multi-stage, interactive, large-scale, high-autonomy into consideration for safely and efficiently integrate the UAS into the national airspace system.