Abstract: An algorithm of vector color-fill between contour lines is proposed based on boundaries of DTM oriented submarine mapping.This algorithm traces and stores DTM boundaries on the basis of processing bizar regrid data, and establishes the bidirectional relationship between DTM boundaries and contour lines through the matrix of boundary points,then establishes the topological relationship among unclosed contour lines and traces the polygons based on the order of boundary points,and creates the nested relationship of polygons by minimum external rectangle of polygons and the method of counting angles which is used to determine the relationship between point and polygon.It is successfully applied in the software MB Chart which is used to process and maphuge volume of submarine topographic data surveyed by multi-beam,and it over comes the inconsistency between color blocks and contours produced by mapping software for multi-beam post-processing.