With its unique advantages, construction informatization is increasingly recognized by the whole industry of engineering and construction. However, compared with the previous 2D design, Revit still has some problems such as inefficiency when its BIM model is applied in engineering design for adjusting pipeline gradient. Referring to the Outdoor Drainage Design Code (GB 50014-2006) Gradient, this paper studies the BIM-based gradient adjustment water supply pipeline through the application of secondary development on Revit.Through the secondary development technology, the corresponding relationship between pipe diameter and slope value is adjusted in batches, which makes the Revit software more efficient and convenient in collaborative work, and meanwhile greatly reduces the error rate. Finally, an engineering example is presented, which provides a reference for promoting the development of BIM software and other technologies.