ACA is the abbreviation of AutoCAD Architecture. It is based on AutoCAD, but designed for Architectural design. It is often called AutoCAD for architects. Using DOT NET API and basing on ACA's intelligent object model, we have developed an application module especially for structural engineers. The structural functions such as creating layout grids, placing members and loads etc are all included. The model created by the structural module can be directly imported to structural analysis software like ETABS to do the analysis job. It is designed for integrating architectural and structural design and analysis. This paper can be used as a reference for the application of BIM technology.