The application of BIM technology is researched for the refined design of dredging project in an overseas port. The 3D dredging model and geological model are established by software Civil 3D to realize the statistics of dredging quantities by soil category and generate standardized construction drawings，while ensuring the dynamic correlation among models，drawings and engineering quantities. Practice shows that the application of BIM technology can greatly improve the precision and efficiency of port dredging design and provide a theoretical basis for the engineering construction.