In order to study the roles of Arabidopsis AtCIPK23 gene played in response to drought stress, we treated three AtCIPK23 gene transgenic lines and wide type tobacco K326 by drought stress. The leaf water loss rate, proline, chlorophyll, soluble sugar contents and electrical conductivity were measured. Meanwhile, ROS elimination ability, and gene expression of ROS elimination and drought resistance related genes were analyzed. The results showed that: (1) the water loss speed of leaves detached from transgenic lines distinctly slower than that of K326. After 7 days of drought stress treatment in natural environment, K326 plants showed yellowish and withered. The rewatering survival rate of transgenic lines was higher than that of K326 after 7 days drought stress. (2) The concents of proline, chlorophyll and soluble sugar in transgenic lines were obvious higher than that of K326. The electrical conductivity of transgenic lines leaves was significantly lower than that of K326. (3) Under drought stress, the accumulation of H₂O₂ in K326 was significantly higher than that of three transgenic lines, and three ROS elimination related genes NtSOD, NtCAT and NtAPX were upregulated only in the transgenic lines. (4) The drought resistance related genes NtAREB, NtLEA5 and NtCDPK2 were induced by drought stress in transgenic tobacco plants. These results suggest that the AtCIPK23 gene can improve the drought stress ability of transgenic tobacco.