The transformation of the global energy structure is the only way to achieve sustainable development, and the development of clean energy technology relies on a variety of critical metal materials. To ensure the development of global clean energy technology and the transformation of the global energy structure, this paper selects 15 critical metals of clean energy technology, establishes a supply risk assessment system from four dimensions of supply reduction, demand increase, geopolitics and social supervision, including 10 assessment indicators. The results show that: (1) the critical metals of clean energy technology are all at medium- risk or above. Among them, the supply risk assessment of indium, gallium and germanium is at a high risk level; 12 metals supply risks of lithium, cobalt, cadmium, selenium, molybdenum, palladium, platinum, copper, aluminum, zinc, iron and titanium are in medium risk level. (2) In the supply reduction risk dimension, six metals such as indium, iron, molybdenum, zinc, germanium, and cadmium belong to medium and high risks, and the risk of indium is the highest; among the risk dimensions of increased demand, the risks of indium, gallium, and germanium are medium to high risks; In the political risk dimension, 9 metals belong to medium and high risks, and cobalt has the highest risk; in the social regulatory risk dimension, 11 metals belong to medium and high risks, and indium has the highest risk. Therefore, it is necessary to establish a normalized risk classification management mechanism for the supply of critical metals and a secondary resource recovery management system as soon as possible, and enhance cooperation with critical metal suppliers to alleviate critical metal constraints for the development of clean energy technology.