Abstract: In order to meet the needs of coordinated land-sea development and unified management of natural resources, and to address inconsistencies in spatial reference, feature classification, spatial characteristics, cartographic portrayal, and topological relationships among fundamental geographic feature data across land and marine domains, this paper systematically reviews the research progress of land-sea integrated map data fusion in China. Through literature review and comparative analysis, this paper summarizes the main technical approaches in terms of harmonization of the geospatial data foundation, semantic integration, spatial feature fusion, cartographic portrayal harmonization, topological consistency processing, and technical support, and summarizes the processing workflow of land-sea integrated map data fusion on the basis of existing studies. The results show that existing studies have provided technical support for the integration and unified portrayal of fundamental geographic information across land and marine domains, but there are still problems, including a limited scope of data fusion, insufficient general-purpose fusion methods, weak quality control, an incomplete standard system, and insufficient coordination between technical methods and management mechanisms. Future research should address the needs of coastal geological surveys and unified management of natural resources, expand thematic data fusion, improve fusion rules and quality-control methods for multi-source heterogeneous data, strengthen the standard system for land-sea integration, promote coordination between fusion technologies and production management mechanisms, facilitate standardized database development and dynamic updating of land-sea integrated map products, and enhance comprehensive service capabilities.