Abstract: Based on the concept of ecological system stablity,relationships of highway construction with key factors of ecological system stability in ecological sensitive areas were analyzed.Spatial patterns of landscape ecology,level of natural productivity and density of dominant biological species were found to be the key factors.A framework and methods for evaluation of impact of highway construction on ecological system stability of the area were put forward.The framework and methods were applied to the study on impact of the construction of Highway 121 that passes through the National Hongze Lake Wetland Reserve.