The knockout and overexpression mutants of OsCPK12 were constructed with reverse genetics. The plant height,root length and leaf phenotype of the overexpressed lines was much better than that of the wild type under the 150 mmol/L NaCl treatment. The plant height of knockout mutants was shorter,the root development were affected,and the leaves were withered and yellow compared with the wild type,indicating that OsCPK12 had positive regulation effect on rice salt tolerance. The results of the expression level of hormone signal transduction pathway genes in different tissues of mutant lines analyzed by realtime PCR showed that expression of multiple hormone receptor coding genes and downstream regulatory genes in the overexpression lines were significantly upregulated compared with the wildtype. It is indicated that OsCPK12 was involved in signal transduction of hormones,which affected rice stress response. Subcellular localization of OsCPK12 was done by fusion expression of target protein with fluorescent protein to further characterize the gene function of OsCPK12 and explain the mechanism. OsCPK12 was proved to be mostly located in the plasma membrane,laying the foundation for further research. Two water channel proteins,OsPIP11 and OsPIP27 were screened from Zhonghua 11’s membrane protein library and its interaction with OsCPK12 was further confirmed with yeast twohybrid test. Results indicated that OsCPK12 may interact with OsPIP11 and OsPIP27 and regulate the entry and exit of water molecules which improve the rice salt tolerance.