Abstract: Role of silicon in regulating crop water loss, activating antioxidant system, enhancing root absorption, promoting mineral nutrient absorption, and regulating plant hormones under drought stress and related physiological mechanisms were reviewed．Under drought stress, silicon regulated drought resistance of crops through a variety of physiological mechanisms and alleviated damage of drought stress to plants．At present, silicon fertilizer has been used in some agricultural production, mainly used for topdressing outside roots and foliar fertilization of some crops, but no specific role of silicon has been found physiologically, and some of potential mechanisms of silicon on improving plant drought resistance are not clear．Future research needs to further reveal detailed mechanism of silicon to improve plant drought resistance, so as to provide a scientific basis and theoretical basis for silicon in improving crop production efficiency．