Abstract: At present, the general finite element software has become more mature, but there is few efficient practical software for specific industry.This article introduces the 3D information model applied in substation gantry design software and expounds the using of SAP2000 API function to realize the independent research and development of special structure of professional design software.It also introduces the use of 3D information model to generate the linkage of the two-dimensional construction method and construction drawing modification, material tables of statistics, the realization of the undo redo operation.This article has practical significance for further development of SAP2000 application, and provides a good guidance of professional custom design software for special structure.