In order to improve the overall positive design ability of ship power engineering, the digital design method of ship power systems engineering is studied. The model-based systems engineering (MBSE) method theory was integrated with the system engineering method, using the independently developed V-Dats software platform and the graphical SysML language, modeling is carried out from four dimensions: requirements, behavior, structure and parameters of the auxiliary system of the generator set. The process analysis of system requirements-function-logic-physics was completed. The system requirement architecture, functional architecture and physical architecture model were obtained, then closed-loop verification and validation were carried out at the system level. By summarizing the top-level framework of the overall design process of ship power systems, an overall forward design method based on MBSE was proposed. The research results can effectively support the overall demonstration and design of ship power engineering.