Considering the rolling motion of nuclear-powered ships， the turbulence flow and heat transfer characteristics of supercritical water in the cooling channel in the core of supercritical-water-cooled reactor （SCWR） under rolling conditions are numerically investigated， in order to reveal the impact of rolling motion on transient and time-averaged heat transfer performance. The results show that the crossflow intensity of the supercritical water is strengthened under rolling conditions. The mass flow rate of the fluid， the pressure drop， the transient heat transfer coefficient and the maximum wall temperature on the outer surface of fuel rod are observed to fluctuate periodically. The impact of rolling motion on convective heat transfer characteristics will be more significant as the fluid temperature gets closer to pseudocritical temperature， and there is positive correlation between the fluctuation amplitude of transient parameters and the ratio of rolling amplitude to rolling period. As the rolling amplitude increases or rolling period decreases， the fluctuation amplitude of transient heat transfer coefficient and transient pressure drop rises. In general， both the time-averaged heat transfer coefficient and pressure drop increase under rolling condition， when compared with the vertical static situation， but the increment is limited.