In the background of industrial pollution increase, ozone hole expansion, green house gases increase, etc. global ecological risk becomes more obvious, making human living environment confront with a severe challenge. Eco-city is actually a form of harmony of human beings and nature, unification of human construction and natural development. And how to build an eco-city is always a key problem. Eco-city planning is an important part of the eco-city construction, which is an effective measure to realize the dynamic balance of the ecological system of city and regulate the relationship between human and environment. Based on the eco-city planning of Shanghang County, this paper does research on the ecological sensitivity analysis. In the analysis, this paper firstly selects eight factors. Then using single factor analysis and superposition algorithm, it gets comprehensive sensitivity regionalization map and classifies the area into five different grades: extremely high sensitivity region, high sensitivity region, medium sensitivity region and weaker sensitivity region. Finally, according to different features in each regions, different regions are classified into three areas: construction prohibited area, construction limited areas, construction appropriate areas. As the core of ecological urban planning, ecological sensitivity analysis focuses on urban planning from natural ecology aspect. Through identifying the sensitive areas, protection planning can be made to protect, preserve and recover these areas. And it can guarantee urban natural foundation from destroyed and promote urban sustainable development.