Driven by the global demand for carbon reduction and ecological environmental protection, submerged water jet propulsion technology has become an important direction for marine power innovation due to its advantages of low noise and high-speed efficiency. This study conducts multi-objective optimization on the preliminary design model of a new-type submerged water jet propulsor using the Central Composite Design (CCD) and response surface methodology, and establishes a high-precision CFD (Computational Fluid Dynamics) numerical model to evaluate its hydrodynamic performance. Verified by cavitation tunnel tests, the optimized propulsor maintains an open-water efficiency of over 65% in the speed range of 25 kn–40 kn, with an efficiency of approximately 75% under the 35 kn operating condition. The research results confirm the excellent performance of this propulsor in complex flow fields, providing theoretical support and a practical paradigm for the design of green marine propulsion systems.