Product quality is crucial in manufacturing, and process parameters are key factors influencing product dimensions, performance, and other indicators. However, the current production processes face challenges such as complex mechanisms, mutual influences among multiple stages, and difficulties in optimizing process parameters. In response to these issues, this paper proposes a multi-stage manufacturing process parameter optimization method based on an improved marine predator algorithm. To address the modeling difficulties arising from the strong coupling of multiple stages in the manufacturing process, a multi-stage modeling strategy is employed. The method utilizes a multi-gene genetic programming (MGGP) approach to explore the nonlinear relationships between process parameters and quality indicators, establishing a multi-stage parameter optimization objective model. To enhance the efficiency of solving the optimization objective model, an improved marine predator algorithm (QNMPA) is introduced. This algorithm utilizes a reverse learning strategy and hybrid control parameters to improve optimization capabilities, aiming to achieve global optimal solutions. Using the rubber extrusion process in a specific factory as an example, the proposed method is validated to effectively address challenges in multi-stage process parameter optimization and improve the stability of product quality.