Abstract: To establish large-scale multi-level database of land use,we propose a new method to generalize polygon roads to polygon-polyline mixed roads.When integrating road polygon datasets,the network road polygons are divided into three types,retention,deletion and reduced maintenance parts.Deletion parts are removed,and the reduced maintenance parts are changed into linear roads,and the retention parts and the linear roads form the new mixed road dataset of the new target scale.Moreover,the deletion and reduced maintenance road polygons will be divided into small pieces and then incorporate into polygons which matches these pieces in order to ensure the land use data having no gaps.