With the development of digital design, 3D modelisfrequentlyintroduced in engineering design. PDMSis a widely used digital collaborative design software,yet withsome limitations inplot plan( such as dealing with natural terrain, etc. ). Theprevailingsoftware of 3Dmodeling in the field ofplot planisCivil 3D. How to import all kinds of 3Dmodels created by civil 3Dinto PDMS, so as to realize the collaborative design ofplot planand otherdisciplines,requires thestudyofsecondary development ofCivil 3Dand PDMS. By extracting the information ofCivil 3Dsurface, the surface information is written into a model file composed ofProgrammable Macro Language(PML), and loaded directly in PDMS to realize the import of surface information. After the introduction, the surface model ofCivil 3Dand PDMS was compared. It was concluded that through the secondary development, the surface model inCivil 3Dcouldbe accurately presented to PDMS to meet the collaborative design.