Abstract: The prefabricated factory produces components based on the detailed design drawings of the prefabricated components, among which the prefabricated composite slabs are the widely used in prefabricated buildings. In response to the current problems of low efficiency in deepening design of prefabricated buildings using CAD software, low accuracy of material data statistics, and large amount of modification work, this study uses the Tekla Structures software platform to create a BIM model of prefabricated composite slabs by reading CAD data using C# language. This solution significantly improves the modeling speed of composite slabs.An example of source code for generating precast composite slabs through secondary development on the Tekla platform, which can read the coordinates of the CAD plane in batches and generate concrete slabs, reinforcement, and truss reinforcement models in batches, can improve the efficiency of detailed design of precast composite slabs.