Abstract: This paper introduces the software extension in the reactor core analysis code PARCS and thermodynamics code RELAP5 to accommodate the special water thermal physical properties and separated moderator channel design in supercritical water reactor (SCWR). The two major results from analysis of the U.S. reference design with the coupled PARCS/RELAP5 were the moderator flow reversal, and the separation of maximum power assembly and maximum cladding surface temperature assembly were given. Based on these results, discussions and suggestions were made on the development of SCWR analysis codes in China.