Abstract: To provide decision-making basis for the protection,restoration and management of middle and lower Liaohe river,we put forward an index system and criteria for the hydroecological integrity assessment. The index system includes minimum expected fill rate of instream flow,zero flow index,environment suitability,sediment concentration,and sediment transport equilibrium index. Fuzzy comprehensive assessment model was employed for the hydroecological integrity assessment. Results showed that the hydroecological integrity of Liaohe river is in an average level.

Key words: Liaohe river , assessment index , fuzzy comprehensive assessment , hydroecological integrity