The Tongbai Xinyang regional geochemical survey is a component part of the nationwide regional geochemical survey. The map compilation involves the collage of No.19 zone and No.20 zone as well as four 1:200000 map sheets, and hence there exist quite a few difficult technical problems in map making. In order to avoid the fissure coordinate inconsistency between the two projection zones, the authors converted the data of No.20 zone to No.10 zone, looked up the natural coordinate values in the Gauss-Kruger coordinate table, and calculated the general coordinate values. On such a basis, the coordinate plotting was performed. The map making result seems quite satisfactory.