Abstract: Silicon is of great significance to the growth and drought tolerance of plants. Drought stress causes water loss of plant and even inhibits plant photosynthesis and the normal growth and development of plants, which leads to the reduction of crop yield and poses serious threats to food safety. Although the silicon has long been considered as an unnecessary element for plants, many studies showed that plants can relieve many kinds of adversity stresses after absorbing silicon. This paper systematically concluded the research status at home and abroad on the role of silicon in plant growth, photosynthesis, osmotic regulation and antioxidant regulation under drought stress. The result showed that the exogenous silicon could effectively improve the synthesis of organic osmotic regulatory substances, alleviate osmotic stress under drought stress, improve the activity of antioxidant enzymes and the content of antioxidant substances to resist oxidative stress so that the drought tolerance of plants could be enhanced. However, current researches on the regulation of plant drought resistance by silicon are mostly on the physiological level. Many molecular mechanisms, such as how silicon regulates the synthesis of plant osmotic substances under drought stress and the activity of various antioxidant enzymes, are still unclear, which are the focus of future studies.