Abstract: In order to analyze the effects of the circumferential heat conduction in fuel rods on supercritical water-cooled reactor (SCWR) fuel assembly, the model of 3D fuel heat conduction was included in the sub-channel analysis code. The results of steady-state calculation of two kinds of SCWR-M fuel assembly show that: The circumferential heat conduction in fuel rods can not be neglected in fuel assembly of thermal zone; the circumferential heat conduction in fuel rods can be neglected in fuel assembly of fast zone.