In the face of mounting anti-globalization trends, frequent local conflicts, and intensifying global climate pressures, ensuring national energy and food security has become an important task to cope with the dynamic changes in the world. However, the current security of supply, which is mainly reflected in the bottom-line thinking, cannot reflect the real-time change of the connotation of "security". To solve this problem, based on the functional data analysis (FDA) method, the paper constructs a security assessment system under the dynamic weight framework, and dynamically evaluates the energy and food security level of 30 provinces from 2003 to 2019. Function-on-function (FOF) regression model is used to further analyze the impact of energy security on food security. The results showed that energy supply and transportation security and economic security accounted for the largest proportion, while the proportion of environmental security increased. The dimension of supply security of food security accounted for the largest proportion, and the weight of related indicators of ecological security increased. Further analysis shows that there is a nonlinear relationship between energy security and food security with the change of the connotation center of gravity.