The cabin ventilation system is one of the important systems in civil aircraft, and its main function is to provide a safe and comfortable cabin environment for passengers in the cabin, mainly including temperature regulation, humidity regulation, and air pressure regulation. This article investigates the current research status of the thermal environment in enclosed spaces and the research status of human thermal regulation models. The JOB-2 human thermal regulation model was introduced and combined with the CFD numerical simulation method to calculate the cabin thermal environment and human comfort. Under the condition of a cabin target temperature of 24 ℃, the air supply temperatures on hot and cold days were calculated. A comparison was made on the air supply methods and an analysis was conducted on the comfort of the cabin human body, guiding the ventilation design of civil aircraft cabins.