Abstract: Drought is an important stress factor, destroys the normal growth of plant. Increasing shortage of water resources becomes serious problem, it restricts the agricultural development. Therefore, the responses of plants to drought stress, especially the drought -resistant mechanisms have been a focus of the studies. In this paper, from the plant physiological response (the changes of root and blade, the influence on photosynthesis) and molecular adjustment mechanisms (osmotic regulation gene, protective enzyme systems and transcription factors) the crop drought resistant mechanisms were reviewed, so as to provide some new ideas and new means for China's water-saving agricultural research.