Shouxihu Drainage basin of Yangzhou City was used to study the ecological processes characteristics of its stormwater runoff and nonpoint pollution. And a system - wide integration of ecological engineerings for urban stormwater treatment was promoted，based on sources - conveyance - pool - discharge patterns of urban runoff "eco - mouth" system. A System for Urban Stormwater Treatment and Analysis Integration Model，SUSTAIN was used on the ARCGIS9.39.3 platform to assess the runoff quantity，water quality effects of the system - wide ecological engineerings based on the integrated thought of “eco - mouth” treatments sysytem construction including source – conveyance - pool – discharge stages. The results show that: 1） The source “eco - mouth” treatments system enabled Shouxihu Drainage basin the average annual maximum peak flow back to the situation before the watershed development，but the reduction of the total runoff volume output was not . TN was reduced by about16.7 % TP was cut to about 15.0 %，COD was reduced by 28.0 %. 2） The conveyance “eco - mouth” treatment system restored the average annual maximum peak flow back to that before the watershed development. TN was reduced by about 74.8 %，TP was reduced by 75.0 %，COD was reduced by 73.4 %，but the annual total runoff volume was not reduced to the development of the status quo ante. 3） The pool “eco - mouth” treatments system made the annual total runoff volume of the basin return to the situation before the development，especially the annual peak flow was less than the development situation. the TN，TP，COD and BOD output load showed a reduction of 83.3 %，80.0 %，83.0 % and 90.0 %，indicating the control efficiency of the storage “mouth” process based integrated management project on runoff quantity and runoff qualify improvement. 4） The Discharge “eco - mouth” treatments system controlled the watershed years of average maximum peak flow well，the peak flow of Shouxihu Drainage basin was less than the situation prior to development and exchange process watershed stormwater management. The TN，TP，COD and BOD output load were reduced by 83.0 %，77.0 %，80.0 % and 81.0 %，showing the reduction efficiency of annual total runoff volume output of the entire watershed. 5） The whole process treatments system integrated source “eco - mouth”，conveyance “eco - mouth”，pool “eco - mouth” and discharge “eco - mouth” restored the annual peak flow and annual total runoff volume back to the the condition before the development. And the whole process integration of ecological engineerings was able to reduce all nonpoint pollution in the basin levels return to the condition before the development. 6） The ecological construction based on green space，wetlands and river ecological infrastructures was the best cost – effective program for ecological compensation of Shouxihu Drainage basin to control the output load of stormwater runoff peakflow，total runoff volume and the nonpoint pollutions.