Paper map and scanned map are the traditional way of map preservation. These methods make spatial query and analysis difficult. It is necessary to vectorize these maps to facilitate the query and analysis of historical geospatial data. However, the traditional vectorization method is time-consuming and labor-consuming, and cannot meet the actual needs. Therefore, this paper proposes an automatic map vectorization method based on boundary tracking. Firstly, the map is grayed and binarized; then the raster to

vector method is applied to the binary map; finally, based on four maps, the extraction effect of this method is compared with common methods. The experimental results show that this method can extract all map lines completely, and can effectively separate the text in the map.