Abstract: RACK1 is a scaffold protein with versatile functions and plays important roles in the regulation of plant growth and development. transgenic rice (Oryza sativa), with the expression of OsRACK1 anti-sense construct, was used to study possible functions of OsRACK1 in response of rice to drought stress. Real-time PCR analysis showed that the expression of OsRACK1 in transgenic rice plants was reduced by more than 50%. The tolerance to drought stress was stronger in transgenic than in nontransgenic rice plants. The epioxidation of membrane and production of malonaldehyde were significantly lower and the superoxide dismutase (SOD) activity was significantly higher in transgenic plants than in non-transgenic plants. OsRACK1 may negatively regulates tolerance of rice to drought stress , which is associated with the redox system in rice.