Abstract: In this paper,the flow field of the wet submersible pump (BQ1100-425) was simulated by ANSYS-CFX,while the grid independence was validated.The numerical simulation results of full passage,single passage,structured grid and unstructured grid were studied respectively,such as the head,efficiency,the pressure and the streamline on the impellers.The results of full passage were more accurate compared with the signal passage,but its calculation time was longer.The signal passage could reflect the flow field characteristics well and its calculation time was shorter.The simulation results of structured grid and unstructured grid were accurate while the precision of the former was better and its calculation time was shorter.While the structure of the wet submersible pump is complex,it is feasible to study its flow field by the signal passage and structured grid modal.