In the past 20 years, China's economy has grown rapidly, but so has the country's power industry. This paper provides a comprehensive introduction on the current status and the future development of the power transmission systems and grids, which include HVAC and HVDC transmissions, regional power grids and grid interconnections, several important operational issues, e.g., stability problems that China's power grids face, new technologies for increasing transmission capacity, and stabilizing the grids, and so on. Under the constructed UHVAC and UHVDC, some pilot projects and planned future development of UHVAC and UHVDC transmission systems are also introduced. (C) 2009 Elsevier Ltd. All rights reserved.