Abstract: Objectives To address the need for lightweight design and vibration reduction in pump-jet propulsors, the study investigates the impact of carbon fiber composite material duct.Methods Composite materials were applied to the ducts of pump-jet propulsors with designed ply configurations. A CFD/FEM bidirectional fluid-structure interaction method was used to calculate the hydrodynamic changes caused by structural deformation, and finite element structural vibration algorithms were employed to calculate the vibration response. A comprehensive analysis and comparison were conducted on hydrodynamic performance, vibration characteristics, various working conditions, and the influence of ply layers.Results The study provided key data such as deformation, hydrodynamic coefficients, and vibration characteristics of composite material ducts, including deformation magnitude, thrust fluctuation changes, and modal frequencies, indicating that composite materials can improve performance.Conclusions The study strongly confirms the role of composite materials in lightweight design, vibration reduction, and performance optimization, providing a basis for the design of propulsors.