Abstract: Aiming to rasterize topological region data in GIS, we present a fast algorithm named as difference boundary-labeling and accumulating-scan algorithm. By the method, at first the system scan orderly all the arcs in the topological region data, and label the boundaries in the raster buffer by means of difference boundary-labeling algorithm. Then all the pixels at each row in raster buffer is filled up from left to right using accumulating-scan algorithm. The algorithm is not only easy to be implemented, but I can also avoid the construction of regions and repeated processing of arcs as it makes full use of the arcs' characteristics. High efficiency could be achieved by using this fast algorithm when rasterizing massive topological region data. In the paper we also discussed the degradation facts and gave our solutions. The experiment showed that the algorithm is practical and highly efficient.