By investigating the characteristic of information repeating in building engineering drawings, a 3d design reusing model is developed to exploit the potentialities. TTie model has the capacity to deal with the vertical repeating and the horizontal repeating. It helps the flat original data in drawings be reorganized into a multi-level tree structure. Each reusable part finds its place in the leaves and is deployed automatically to where it should reappear through the branches in the tree. Software system based on the model employs thewblock-reference, 5function in AutoCAD to store the reusable parts and implement the assemblying action. It helps to save all the copies for the repeating information to achieve the synchronous modification. More advanced functions such as automatical printing for standard floors have been involved in the system. TTie statistic on practice shows that it can enhance the efficiency by more than 50%.