<p>Land-based pollution output zoning is crucial for the integrated land-sea management and coastal sustainable development. In special coastal regions such as peninsulas or islands, which are characterized by more complex hydrology, the coastline area occupies a larger proportion due to their extended shorelines, a factor that has often&#xa0;been ignored in previous studies. We established a framework for the spatial zoning of land-based pollution output: Firstly, we used the optimal threshold method to divide watershed zones; Secondly, we divided coastline zones based on “source-sink” theory; At last, combining watershed zones on land and zones around coastline, we determined the land-based pollution output zoning on foundation of the spatial relationship of “watershed-estuaries(coastline)-bay(nearshore)”. Taking the Southern Liaotung Peninsula as the study area, our results revealed that: (1) Using a river network and a catchment area of 10 km² as the optimal threshold, 52 watershed zones were extracted; (2) The coastline areas accounting for 19.26% of the total study area, 330 coastline zone units were divided, and the coastline zones were mainly characterized as “source” landscapes, accounting for 76.17% of the entire shoreline area; (3) The Southern Liaotung Peninsula could be divided into 41 land-based pollution output zones with different features of the land and the nearshore water quality, and relevant measures and suggestions could be proposed based on the corresponding land use features, shoreline area utilization and nearshore water quality. Our research not only provided a new perspective and framework for environmental governance and management in coastal regions, especially for peninsulas and islands, but also provided scientific reference for land-based pollution risk prevention based on land-sea coordination.</p>