Drought stress can significantly affect plant photosynthesis, metabolism, osmotic regulation and other related physiological processes, and then affect plant economic traits. Exogenous ABA can alleviate the effect of drought on plant growth. We selected the exogenous ABA as the main discuss basis, this paper expounds the exogenous ABA increase crop physiological mechanism of drought resistance. The regulation of photosynthetic physiological by exogenous ABA in drought stress was introduced, and the induction of gene expression, the regulating the osmotic regulation substances content and the activity of protective enzyme and the important role of physiological and biochemical process. Taking exogenous ABA as the starting point to regulate crop drought, this study discussed the current situation and trend of ABA research in the field of plant drought resistance, which is of great significance for water-saving, drought resistance and yield increase of plants, and also provides theoretical basis for future studies on agricultural production drought resistance.