In order to improve design efficiency and statistical accuracy of excavation volume in dredging design of waterway engineering,we develop a 3D aided dredging design system for waterway engineering based on partial achievements of harbor investigation and design application system(HIDAS).The system combines 3D geological model and 3D CAD technology,and provides multiple functions including parametric intelligent modeling,automatic statistics of excavation volume,generating batch excavation section drawings and so on.We apply this system to the dredging design process in the expansion project of east channel of Qinzhou port,and achieve that the design sections can be generated automatically with different excavation slope ratios and different extra-deep and wide parameters according to different soil quality,excavation volume,extra-deep and wide excavation volume of different sections and different soil classification can be calculated separately,excavation section drawings with CAD format of different sections can be generated batch automatically.The system can greatly improve the design efficiency and quality.