According to present conditions and characteristics of regional fragile eco-environment and analyses of the factors influencing fragile eco-environment, a quantitative assessment index system for Gansu Province is set up and the weighting value of each index is confirmed.By calculating fragile degree of eco-environ-ment, the major problems and causes in different fragile eco-environment regions are analyzed to provide a scientific gist for protection of eco-environment.The study is helpful to the sustainable development of socie-ty and economy in Gansu Province.