Abstract: A method for optimization design of water-jet propulsion systems based on pump database is developed. The guiding factor lies in the establishment of a database of existing pump models having distinct performances. According to the technical requirements of amphibious vehicle water-jet propulsion systems, the model pump that meets the performance requirements from the database is selected and optimized. The method is universal and provides a theoretical foundation for the design and thorough study of amphibious vehicle water-jet propulsion system. The method has been applied to the optimization design of an amphibious vehicle to meeting the expected requirements of the vehicle.