In order to achieve 3D visualization of the ground surface and stratum of Dayaoshan tunnel, the following 2 topics are studied in particular in the paper:  studying on effective format conversion methods so as to convert AutoCAD format graphics files, which are often used in engineering, into proper format files required by the 3D geological modeling software;  Based on the AutoCAD format data of the contour map and longitudinal geological profile of Dayaoshan tunnel on Wuhan-Guangzhou passengerdedicated railway, 3D ground surface model, 3D stratum model and 3D tunnel model are established for the tunnel by means of the 3D geological modeling software. The research lays a sound foundation for further study and development of the 3D visualization of the tunnel stratum in the future.