[Objective] Crops often suffer from interval drought and rehydration (rainfall or irrigation) during the whole growth period, especially in arid and semi-arid areas. Under drought stress, the growth and development of crops are inhibited, and the yield is reduced; meanwhile, the plants drought tolerance will be induced. In order to compensate loss of yield or growth induced by drought stress, crop often shows compensatory after rehydration, which produces compensation or even over compensation effect on yield. The compensation effect of post drought is the result of crop’s positive response to drought stress and compensatory growth after rehydration. It can effectively improve crop yield and water use efficiency in crop production in arid areas. [Methods] Source sink relationship is widely used to explain the crop yield formation, and regulating the source sink relationship is one of key way to improve crop yield. The compensation effect of post drought is highly related to the source sink response of crops. Based on the current research progress, this paper tries to explain the compensation effect of post drought in source and sink way. [Results] Under the drought stress, in the source, the stomata were closed, photosynthesis was decreased and soluble carbohydrate accumulation was increased, while sink activity was often increased. After rehydration, the metabolism of soluble carbohydrate in the source (leaf) was enhanced, which enhanced the photosynthesis and the ability of carbohydrate synthesis; meanwhile, the sink activity (grain) was maintained at a high level, and the rate of assimilate unloading and accumulation was accelerated; the assimilate in the flow remained at a high level. During this process, the activities of sucrose invertase (INV), cell wall invertase (CW-INV) and fructan exohydrolases (1-FEH w3) play important roles in the source sink response to the compensation effect of post-drought. [Conclusion] This paper integrated the mechanism of compensation effect of post drought in the perspective of source sink relationship, which provides a theoretical basis for understanding the mechanism of compensation effect of post drought and improving crop water efficient in arid areas.