Abstract:Taking the catchment area along the Weihe River in Shaanxi Province as a study area, and on the basis of elementary principles of risk and the theoretical framework on regional ecological risk assessment, calculative model was established to obtain integrated ecological risk value which was computed by the integrated risk probability, integrated eco-damage, and integrated socio-economic vulnerability. Based on the historical data in study area and landscape classified image of ETM+ in 2002, by selecting four risk sources of drought, flood, pollution and soil erosion, using GIS and a variety of mathematical models and methods, according to assessed steps and calculative model, this paper divided general risk assessed results mainly into five grades, that is, the lowest risk region, lower risk region, moderate risk region, higher risk region, and the highest risk regions. The results can provide quantitatively theoretic basis and data support for environmental management and ecological risk decision-making, and it has an important reference value.