Nuclear-powered ships play a significant role in maritime transport due to their unique advantages in energy supply. This paper focuses on the integration and optimization of a combined cooling, heating, and power generation (CCHP) and desalination system on a nuclear-powered ship, proposing an innovative design solution that achieves an integrated energy and resource supply on board by optimizing the distribution of steam generated by steam generators. In the system design, steam is efficiently distributed to a low-pressure steam generator for heating, a nuclear power generation system for electricity generation, and an absorption refrigeration system for cooling. In addition, considering the ship's demand for freshwater resources, the possibility of coupling the CCHP system with a direct contact membrane distillation (DCMD) system is discussed to utilize low-grade thermal energy for seawater desalination, which further enhances the efficiency of integrated energy utilization. By establishing a mathematical model of the system and performing numerical simulations, this paper provides an in-depth analysis of the thermodynamic characteristics of the system and parameter optimization, confirming the technical feasibility of the integrated system. In addition, a multi-parameter thermodynamic analysis of the circulatory system is carried out to explore the influence of key parameters, such as main steam pressure and split ratio, on the performance of the system. This study provides a theoretical basis and practical guidance for the design and optimization of integrated energy systems for nuclear-powered ships.