The new round of forest land protection and utilization planning requires taking the results of the third national land survey as the unified base map,and that the territorial spatial planning together with the three zones delineated by three lines for land use as the basis,to scientifically and reasonably clarify the management boundary of forest land.Taking Yanqing District of Beijing as an example,this study establishes a methodology for defining base data for forest land protection and utilization planning in accordance with policy regulations,following the technical requirements,uniting multi-source data,and defining the forest land boundaries.Multi-source forest-related vector data were collected,and then preprocessed through spatial overlay analysis,hierarchical layer union and linking attributes by using the ArcGIS platform.After that,land use is analyzed,screened,and defined one by one according to different attributes in the joint database.Boundaries are then processed and fragmented plots are merged alternately to define the management boundaries of planned forest land and supplementary forest land.Finally,the new base map for forest land protection and utilization planning in Yanqing District is obtained.This methodology provides a valuable reference for defining base data in forest land planning in other regions.