以京津冀地区为研究区域，选取28个代表性指标，利用层次分析法构建水-能源-粮食耦合安全综合指标体系，运用耦合协调度模型和障碍度模型分析2000—2020年水-能源-粮食系统耦合安全性和影响因素。研究结果表明：京津冀地区水安全、能源安全和粮食安全系统综合评价指数呈整体上升的趋势，其浮动范围为0.3~0.7；水-能源-粮食系统耦合协调度年际间均呈上升趋势，北京市耦合协调度最高，河北省耦合协调度较低；人均水资源量、废水中COD排放量、人均能源消费量和亩均农用机械总动力为京津冀地区主要障碍因子。未来北京应调整用水结构、挖掘节水潜力。天津市和河北省要注重优化能源消费结构，进行低碳技术创新，加大脱碳步伐，其中河北省农业发展需要进一步采取节水灌溉措施、减少农作物受灾面积。

Water, energy and food are the three material bases and strategic resources for the survival and development of human society. The United Nations predicts that global food and energy demand will increase by 60% and 80% respectively compared with 2016 by 2050; global water demand is expected to increase by 20% to 30%, with more than 2 billion people living in countries with severe water shortages. Beijing-Tianjin-Hebei region is one of the regions with the most significant "Water-Energy-Food" link and the most prominent joint risk in China, with a shortage of water resources and a large consumption of energy and food. With 0.7% of the country's water resources, it carries 8% of the country's population, 8.2% of the irrigated area and 10% of the total economy, which makes the security of the Water-Energy-Food system very tense. Therefore, the scientific and quantitative evaluation of the coordination degree of Water-Energy-Food coupling in Beijing-Tianjin-Hebei region and the analysis of the main obstacle factors of Water-Energy-Food coupling security are not only the key to improve the security of regional Water-Energy-Food system, but also an important link to adhere to sustainable development.Based on the collected data of the Beijing-Tianjin-Hebei region from 2000 to 2020, the key research and analysis of the Water-Energy-Food coupling security in the Beijing-Tianjin-Hebei region is carried out. The analytic hierarchy process was used to establish a comprehensive evaluation index system for Water-Energy-Food system security coupling, and the evaluation indicators were divided into water security systems, food security systems and energy security systems. The entropy weight method is used to determine the weight of each indicator; the comprehensive evaluation index of the Water-Energy-Food system in the Beijing-Tianjin-Hebei region and the characteristics of coupled security and coordinated development are analyzed through the coupling coordination degree model; and the obstacle degree model is used to analyze the influencing factors in the study area.The results show that the comprehensive evaluation index of water security, food security and energy security system in Beijing-Tianjin-Hebei region shows an overall upward trend from 2000 to 2020, and its floating range is 0.3?0.7. The floating range of Beijing comprehensive evaluation index is the largest (0.3?0.8), Tianjin comprehensive evaluation index is the smallest (0.4?0.7), and Hebei comprehensive evaluation index fluctuates between 0.3?0.7. The results of coupling coordination degree show that the coupling coordination degree of Water-Energy-Food in Beijing-Tianjin-Hebei region shows an upward trend from 2000 to 2020, and there are obvious differences between regions. Among them, the coupling coordination degree of Beijing is the highest, while that of Hebei Province is poor. The result of the obstacle degree of Beijing, Tianjin and Hebei as a whole and each region can be roughly divided into three stages: the fluctuation stage from 2000 to 2005, the transition stage from 2006 to 2015, and the stable stage from 2016 to 2020. Per capita water resources, COD discharge in wastewater, per capita energy consumption and total power per mu of agricultural machinery are the main obstacle factors.Based on the above analysis, Beijing's water security system, Tianjin's energy system, and Hebei's energy security system and food security system are the keys to the overall coupling and coordination of the Beijing-Tianjin-Hebei region. In the future, Beijing should improve water use efficiency, adjust water use structure, and tap water-saving potential; Tianjin and Hebei Province should focus on improving energy recycling efficiency, optimizing energy consumption structure, and carrying out low-carbon technology innovation to increase the pace of decarbonization; Hebei Province also needs to save energy, irrigation measures of water-saving, protect crops, reduce the affected area, and improve the efficiency of agricultural machinery.