In order to provide theoretical basis for the reasonable planting and water management of walnut production, this study analyzed the water consumption and photosynthetic characteristics of transpiration of walnut response to rainfall change. Through the artificial rainfall simulation environment (-50%, -25%, CK, +25%, +50%), pot seedling weighing method and a Li-6400 portable photosynthesis system measuring method were adopted to study transpiration of water consumption and photosynthetic characteristics of Xiangling, Qingxiang, and Liaohe1 seedling under different rainfall conditions, and use the membership function method to analyze the indicators. Results showed that:(1) The water consumption and water consumption rate of Xiangling, Qingxiang and Liaohe1 seedlings showed significant difference under different rainfall conditions (P<0.05), and the difference of water consumption at night was also obvious. The seedlings of Liaohe1 showed the largest water consumption at night in each rainfall condition, small water consumption rate, and good water holding capacity. (2) Under different rainfall conditions, the change of net photosynthetic rate (P_n) of Qingxiang and Liaohe1 seedlings was mainly limited by stomatal factors. Under water scarcity and extreme humidity, the change of net photosynthetic rate(P_n) of Xiangling seedlings was mainly limited by non-stomatal factors. (3) The water use efficiency (WUE) of Liaohe1 seedlings was at a higher level; the WUE of Xiangling seedlings was low in the rainfall increased by 50%; the WUE of Qingxiang seedlings increased sharply in the rainfall reduced by 50%. (4) Combining with the ranking of subordinate function results, Xiangling seedling was suitable for the water conditions that are relatively moist, Qingxiang seedling could grow in the extreme environment lack of water, and Liaohe1 seedling was with high adaptability in different rainfall conditions.