Abstract: The additional force arising from rolling motion causes the change of two-phase flow resistance. The characteristics of air-water mixture flow resistance in narrow rectangular channel (40 mm×1.6 mm) in rolling motions were experimentally studied with the rolling periods of 8 s, 12 s, 16 s and the angles of 10°, 15°, 30°, respectively. The experimental results show that the transient frictional factor changes periodically. The larger the mass quality and the maximum rolling angle and the smaller the rolling period, the larger the fluctuation amplitude of frictional pressure drop. A new correction for predicting the transient frictional factor of two-phase flow in rolling motion is proposed with a good accuracy.