Abstract: The cationic peroxidase change was studied at fertile transformation stage of Nongken 58s rice (Oryza sativa L.subsp japonica)at the different condition of the illumination.The result shows that cationic peroxidase activity increases to be depended on progress of young panicle development.It has a high value in the condition of nature long illumination(i.e.58s-ND)than that in short day(i.e, 58s-SD).Five bands of cationic peroxidase isozymes were separated and can be seen in gel electrophoresis zymogram at the two stages(differentiation of primary brache primordum (Ⅱ)and meiotic division(Ⅳ)of pollen mother cell).At the stage of differentiation of primary brach primordun activity of the fourth and fifth band in condition of NDis stronger than in SD.But at meiotic stage of mother pollen cell,activity of fourth band in SDwas increased.However activity of the fourth and fifth band of the isozymes in NDwas still stronger than that in SD.It may reflect that the effect of illumination condition on the cationic peroxidase isozymes in photoperiod sensitive stage of fertile transformation in Nongken₅₈s is mainly related to the fourth and fifth band of zymograms.