Abstract: Increase in cell membrane ion leakage was induced by Methyl Viologen-mediated photooxidation in two rice cultivars, ‘Shanyou63'' (developed hybrid cultivar) and ‘Peiai64S/E32'' (super high-yielding hybrid cultivar). More increment of cell membrane leakage was shown in ‘Shanyou63'' than that in ‘Peiai64S/E32'' which means less damage to cell membrane in ‘Peiai64S/E32'' than in ‘Shanyou63'' under photooxidation.‘Peiai64S/E32'' had higher values of photosynthetic oxygen evolution competence (Amax,Φi)、PSⅡ activity (Fv/Fm, ΦPSⅡ) and chlorophyll fluorescence quenching coefficient (qP, NPQ) and less reduction under photooxidation in comparison with ‘Shanyou63''. In addition, ‘Peiai64S/E32'' had as much as 3 folds increase in activities of SOD and APX than ‘Shanyou63'' under photooxidation. These results indicated that super high-yielding rice ‘Peiai64S/E32'' exhibited more resistance to photooxidation mediated by MV than ‘Shanyou63''.