Abstract: The thermo-structural performance of the first wall for DEMO （Fusion Demonstration Reactor） blanket cooled by supercritical water was investigated. A coupled code CFX/ANSYS Workbench was used to analyse the temperature and stress distributions of structural material while different geometrical configurations of flow channels were applied. Based on the results achieved so far, an optimized design scheme is suggested on the modification of the design structure and geometric configuration of flow channels, which can effectively reduce the maximum temperature and stress of the structural material.