Abstract: Based on ecological restoration of Lingjiabang River in Kunshan as test objects，the river ecosystem in-situ restoration was tested． In the test，integrated aquatic plant restoration technology and bioflim technology were used so as to improve water quality． Degradation and transfer of organic matter in river waters were promoted by means of balancing plankton species composition and quantity． The results showed that in the case of the river exogenous contamination，the quality of river water had been improved significantly by using in-situ ecological restoration technology． The main water quality indexes such as the water transparency，water chemical oxygen demand ( COD) ，total phosphorus( TP) ，total nitrogen( TN) ，ammonia nitrogen ( NH+ 4 －N) ，chlorophyll-a were reached or excelled to the standard of the landscape water quality．