[Objective] This study aims to investigate the construction of the water ecological security pattern in ecological protection，restoration，and sustainable development of river basins. [Methods] Taking the Liao River main stream basin as a case study，three water ecological services with hydrological transmission characteristics， namely water yield，water purification，and soil conservation，were selected. Based on the ″source-flow-sink ″ conceptual framework，the InVEST model was employed to quantitatively assess the supply-demand relationship of water ecosystem services to identify the ″sources ″and ″sinks ″. The circuit theory was utilized to identify ecological corridors，ecological pinch points，and barriers mediated by water flow. Ultimately，the water ecological security pattern of the river basin was constructed. [Results] The total area identified for the three water ecosystem services is 12 200 km² for the ″source ″and 4 900 km² for the ″sink ″；there are 287 tree-like and network-like ″ flows ″，primarily extending from the main river to the tributaries；there are 79 ecological pinch points and 111 ecological barrier points. [Conclusion] The research findings provide a basis and strategies for zoning and classification，identification of key areas，and layout of restoration projects in river basin ecological restoration.