Abstract:As China's power transmission technology matures, UHV transmission technology has shown the unique advantages in optimizing energy resources, air pollution controlling, and achieving sustainable human development. So UHV grid engineering practice has entered a rapid, large-scale development of new stage in our country. At present, State Grid Company of China (SGCC) has built and put into operation "three AC four DC" UHV projects, and they are constructing “four AC five DC" UHV projects (including "four AC four DC" projects which are involved in national air pollution control program), and the construction practice developed from earlier one line to a new stage of simultaneous construction of multiple lines. Under the background of large-scale construction, there are huge challenges for key resources and critical management processes. In this paper, starting from the key management processes, based on the risk map approach, on the basis of identifying the key processes risk, we carried out quantitative assessment of the risks. We proposed risk control measurements based on the "three elements of management" framework we formulated and the results of risk assessment. Through quantitative evaluation of risk, we clarified the attention focus of large-scale UHV grid construction, and it pointed out the direction for the future to strengthen risk prevention and control, to ensure the goal of large-scale construction.