Abstract: The Supercritical-pressure Light Water Cooled Reactor（SCWR）is selected by the Generation IV International Forum（GIF）as one of the six Generation IV nuclear systems that will be developed in the future,and it is an innovative design based on the existing technologies used in LWR and supercritical coal-fired plants.Technically,SCWR may be based on the design,construction and operation experiences in existing PWR and supercritical coal-fired plants,which means that there is no insolvable technology difficult-ties.Since PWR technology will be adopted in the near term and medium term projects in China,and considering the sustainable development of the technology,it is an inevitable choice to research and develop the nuclear system of supercritical light water cooled reactor.