We used Xu rice No.4 as materials, Oryza sativas transient expression vectors were constructed and the method of bioinformatics and RTPCR were used to design the semiquantitative and quantitative primers of five OsCaMs. We identified the OsCaMs gene induced by ABA and analyzed its physiological function to lay the foundation for further research on the core components of ABA signal transduction. （1）The results showed that their CDS are 450 bp. Treatment with 100 μmol·L_-1ABA could induce the gene expression of OsCaM11 and OsCaM12 obviously. （2）The vectors (35SOsCaM11YFP, 35SOsCaM12YFP) were then transformed into rice protoplasts by PEG method. Subcellular localization analysis by confocallaser microscopy showed that the two genes are located in the nucleus, cytoplasm and plasma. Then the doublestranded RNA interference (RNAi) of OsCaM11 and OsCaM12 were constructed. （3）The analysis of transient expression and RNAi silencing of OsCaM11 and OsCaM12 in rice protoplasts indicated that OsCaM11 and OsCaM12 required for ABAinduced have an obvious influence on the activities of ascorbate peroxidase (APX) and superoxide dismutase (SOD). The activities of antioxidant protective enzymes APX and SOD in rice protoplasts were significantly increased by 35% and 31%, respectively, after ABA induction, overexpressing the two genes in the protoplasts resulted in a fold increase in APX and SOD activities between 1.15 and 1.45 fold. APX and SOD activities were reduced by between 25% and 30% when silencing OsCaM11 and OsCaM12. （4）Treating the rice with H₂O₂, we found that exogenous H₂O₂(10 mmol·L_-1 ) treatment can induce gene expression of OsCaM11 and OsCaM12. And overexpressing OsCaM12 in protoplast increased the production of H₂O₂. （5）The analysis of transient expression in rice protoplasts showed that overexpression of OsCaM11 and OsCaM12 can induce gene expression of OsrbohB and OsrbohE; while overexpression of OsrbohB and OsrbohE can induce gene expression of OsCaM11 and OsCaM12.So between OsCaMs and Osrbohs exists a positive feedback regulation mechanism. Overall, OsCaM11 and OsCaM12 are homologous genes involved in the regulation of antioxidant defense by ABA, these 2 genes can regulate the activities of oxidative protective enzymes in ABA signaling. OsCaM11 and OsCaM12 are induced not only by ABA, but also by H₂O₂ and they are induced by ABA through H₂O₂.