The identification of rural territorial functions of major agricultural areas can provide an important support for rural revitalization and food security. The Jianghan Plain is one of the main agricultural areas in China and is undergoing a rapid rural transformation and reconstruction. From the perspective of ecological, production, and living spaces, this study constructed an indicator system for the assessment of production, living, and ecological functions of rural areas. Using the entropy weight method to determine the weights of indicators, we examined the pattern of change of rural territorial functions in the rural areas of the Jianghan Plain from 2000 to 2015. The influencing mechanism of change was analyzed by applying spatial econometric models. The results show that: 1) The total index value of rural territorial functions of the rural area in the Jianghan Plain increased notably. Values of the three sub-index of production, living, and ecological functions increased by 78.26%, 34.25%, and 9.69%. Growths in the production function and living function were the two main ways of rural function improvement in the Jianghan Plain. 2) The rural function index values of the Jianghan Plain showed prominent spatial differentiation, with an overall east-west divide. Specifically, counties dominated by ecological function mostly aggregated on the northern fringe of the Jianghan Plain, while those dominated by living function aggregated on the central and southern part of the Jianghan Plain, and those dominated by production function showed a random spatial distribution. Ecological function and living function played a major part in the change of rural functions in the Jianghan Plain. 3) We argue that the factors that affect rural development can be divided into two types, namely exogenous driving forces and endogenous responses. The results of the spatial econometric models indicate that both types have an impact on the change in rural territorial functions in the Jianghan Plain. More specifically, the exogenous factors showed a positive influence on the change of rural function in the Jianghan Plain, while the endogenous factors showed a negative effect. The greatest impacts of both the exogenous and the endogenous factors were on production function, followed by living function and total function. The marketization response had spatial spillover effects on the change of rural territorial functions of the Jianghan Plain. Our findings indicate that developing multifunctional agriculture in the Jianghan Plain is a rational choice. In practice, exploring change and influencing mechanism of rural territorial functions for major agricultural areas, on the one hand will be helpful for identifying different patterns of rural development and providing guidance for the implementation of rural revitalization. On the other hand, research on functional types of rural areas could have a broad impact on rural development and urban and rural coordination. Due to the differences in major territorial functions and external conditions, we suggest that the applicability of the evaluation index system and influencing mechanism should vary along with the territorial types.