Abstract: A 1000 MW supercritical water-cooled reactor（SCWR） design concept CSR1000 with independent intellectual property has been developed based on the existing technologies of ABWR,PWR and SCWR.In order to simplify the structural design and obtain more uniform moderation,the CSR1000 standard fuel assembly cluster is built of 4 small size square fuel assemblies,and each of them has only one water rod.Furthermore,a two-pass coolant flow scheme is adopted to increase the coolant flow stability and core averaged outlet temperature.The core consists of 157 fuel assembly clusters,and the out-in loading pattern is employed.After core conceptual design evaluation,these key parameters of the core such as cycle length,average discharge burnup,core coolant averaged outlet temperature,maximum fuel cladding temperature and maximum linear power density have been presented.