Through the case study of the wetland in the Huanghe River (Yellow River) delta,the concept of regional ecological risk assessment is inquired into,and a set of assessment method was developed.

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.

This paper reviewed the concept, definition, main contents, and development process of regional ecological risk assessment, and discussed the key issues in related researches, e.

Exotic plant invasion and its ecological risk assessment;

Distribution and ecological risk assessment of polycyclic aromatic hydrocarbons in surface sediments from Bohai Sea, China;

Establishment of the changeable weight combination forecasting model and its application in regional ecological risk forecasting.;

During the past 20 years,with more studies on the ecological risk assessment,the theories and methods of the regional ecological risk assessment improves greatly,meanwhile the ecological risk management receives widespread attention increasingly.

Based on some foreign standards of soil PAHs assessment,regional environment risk assessment of topsoil PAHs in Tianjin Area was discussed using the method of indicator Kriging.