With the rapid development of inland river shipping, the total number of vessels has significantly increased, making the working and living environment for crew members more important than ever, especially in terms of creating a comfortable and healthy cabin environment. This paper takes a region in Kunming as an example, analyzing the climatic characteristics of the area, particularly the influence of factors such as solar radiation on the ship’s air conditioning and ventilation system, in light of its unique geographical features of low latitude and high altitude. Considering the layout of the ship’s cabins, where some areas are more concentrated and others are more scattered, the proposed design incorporates three different types of systems: Multi-split air conditioning, split-type air conditioning, and water-cooled air conditioning, complemented by an efficient auxiliary ventilation system. While ensuring the comfort of the crew, this design also fully considers the ship’s environmental requirements, improving energy use efficiency, reducing energy consumption, and thereby enhancing the ship’s economic performance. Furthermore, the scheme not only ensures crew comfort under the complex plateau climate conditions but also improves air quality, preventing discomfort caused by excessively high temperatures. This design approach provides valuable experience and theoretical guidance for future air conditioning and ventilation system development on vessels operating in high-altitude lake regions, playing a crucial role in optimizing the ship’s environmental performance, energy utilization, and comfort. It offers strong support for the development of related technologies in the maritime field.