Abstract: Cytoplasmic male sterility(CMS),which eliminates the possibility of self-pollination,is a commonly observed phenomenon in the plant kingdom and has been exploited for hybrid seed production.Rice(Oryza sativa L.) is one of the most important food crops in which CMS has been used successfully for commercial hybrid seed production.Two dimensional gel electrophoresis technique was used to investigate the protein expression profile in uninucleate-stage and binucleate-stage anthers of the rice CMS line(YTA).After silver staining and analysis by PDQuest 2DE software,about 1800 protein spots,including 241 differentially accumulated spots,were detected reproducibly.Out of those differentially accumulated spots,125 spots were specially accumulated in uninucleate-stage,13 spots were specially accumulated in binucleate-stage,and 70 spots were down-regulated and 33 spots were up-regualted in binucleate-stage.The results showed that proteins distribution of uninucleate-stage and binucleate-stage anthers were similar and the protein spots were mainly focusing on pI 4.5-8.0,and molecular weight ranging from 25.0 kD to 70.0 kD,and 41protein spots in this area were analyzed.