The effective utilization coefficient of irrigation water is a crucial indicator for evaluating the efficiency of irrigation systems. Based on the grey system theory，this study focuses on Jiangxi Province and its five agricultural regions，analyzing the spatiotemporal variation characteristics of the effective utilization coefficient of irrigation water from 2011 to 2022 in Jiangxi Province. The grey prediction model was used to forecast the coefficient for the period from 2024 to 2035. The results show that from 2011 to 2022，the coefficient demonstrated a yearly increasing trend in Jiangxi Province and its five agricultural regions，with the largest increase in the Gannan district and the smallest in the Poyang Lake district. The gap between Jiangxi Province and the national average has been gradually narrowing. From 2024 to 2035，the effective utilization coefficient of irrigation water in Jiangxi Province is expected to increase from 0.541 to 0.611，satisfying the requirements of the province's water security planning and the construction of a watersaving society. By 2035，the regions with the highest and lowest agricultural water efficiency will be the Gannan district and the Poyang Lake district，respectively. The findings of this study can provide scientific references for implementing the dual-control action of water resources and constructing a water-saving society.