Abstract: Mathematic analysis and RELAP5/MC code were conducted to investigate effect of rolling motion on oscillation between double parallel channels under dissymmetry heating condition. The results show that rolling period and 1/2 rolling period flow oscillations are induced by rolling motion. When the flow oscillation period is close to the connatural thermo-hydraulics oscillation period of system, the density wave oscillation will happen earlier because of resonance. Increasing rolling amplitude and the distance between channel and rolling center can increase the flow oscillation amplitude and decrease the system stability.