Abstract: With the rapid development of wind power and solar power generation as well as steady development of AC and DC transmission lines,China’s power system exhibits two important characteristics and trends:high proportion of renewable energy and AC/DC hybrid power grid in recent years.Based on an analysis of the present development and existing problems concerning collaborative optimization operation of AC/DC hybrid system with a high proportion of renewable energy,the key technologies demanding prompt research in four aspects are proposed,respectively.That is,situation awareness of AC/DC hybrid system under dual uncertainties of source and load,coordinated control of large renewable energy clusters considering the broadband stability constraints,flexible reconfiguration and cooperative operation with the interaction of source-grid-load in distribution systems with a high proportion of renewable energy,and multi-scale operation optimization and decision making in AC/DC hybrid system with a high proportion of renewable energy integrated.Difficulties and challenges are previewed.