Abstract: Ecological vulnerability has become a hot issue of the research on the global change and sustainable development. The hilly area of southern China is a typical ecologically fragile area. The paper takes Hengyang Basin as an example, and adopts principal component analysis to study the driving forces of the agricultural eco-environmental vulnerability. First, we define the concept of the agricultural ecology vulnerability (AEV), and analyze the contents of the AEV. Then, based on the characteristics of agricultural eco-environment, we establish the AEV indexes for the Hengyang Basin in the southern China hilly areas, which include natural factors, social factors and economic factors, and take county as the evaluation unit. Principal component analysis is an important method in multivariate statistical analysis. Hence, we adopt this method to study the driving forces of the AEV in this paper, and explore the mechanism that causes the vulnerability. The results show that there are four principal driving forces affecting the vulnerability of agricultural eco-environment of this area. The natural environment and economic development background are the primary driving forces, and living standards and agricultural water facilities are the secondary forces. From the view of driving force type, the stress-type driving force is dominant, and the structure-type driving force is minor. Backward mode of production is a powerful driving force of the AEV.

Key words: agricultural eco-environment, driving force, Hengyang basin, principal component analysis, vulnerability