The construction of water ecological security pattern is of great significance to the ecological protection, restoration and sustainable development of the basin. In this paper, we take the Liaohe River Basin as an example, and select three water ecosystem services with hydrological conductivity characteristics: water production, water purification and soil conservation. Based on the conceptual framework of “source-flow-sink”, we use the In VEST model to quantitatively assess the supply-demand relationship of the water ecosystem services in order to identify the sources and sinks, and the circuit theory to identify ecological corridors, ecological pinch points and obstacle points through the medium of water flow. The In VEST model was used to quantitatively assess the supply-demand relationship of water ecosystem services to identify sources and sinks, and the circuit theory was used to identify ecological corridors mediated by water flow, as well as ecological pinch points and obstacles, and to construct a watershed water ecological security pattern. The results show that the “sources” of the three water ecosystem services cover an area of 12,200 square kilometers and the “sinks” cover an area of 0.49 million square kilometers, while the “streams” form 287 service streams in the form of trees and networks, with a total area of 1,000 square kilometers. There are 287 network-like service streams, mainly along the dry river to the tributaries; there are 79 ecological pinch points and 111 ecological obstacle points. The results of the study can provide a basis and strategy for the classification of watershed ecological restoration zones, identification of key areas, and layout of restoration projects.