When it is a bit hot in the vehicle during the driving process, the closed cabin temperature still needs to be cooled down. Though the use of car air-condition can cool down the closed cabin temperature, it needs to start and stop the compressor frequently, which increases the parasitic power of the engine and shorten the life-span of the compressor. With the use of semiconductor auxiliary cooling system to regulate the cabin temperature, the system noise is small and the temperature control precision is high. But the system is inefficiency and the energy consumption is high. This research considered the effects of different body heat producing and transferring characteristics, environment temperature and vehicle speed on the capacity of the system overall, and made the semiconductor auxiliary cooling system in a range of low power consumption under the condition of ensuring human comfort. Firstly, the model of human body heat dissipation is established and the refrigerating capacity of the semiconductor auxiliary cooling system is confirmed under the condition of human comfort. Based on the Peltier effect of the semiconductor and combined with the semiconductor’s heat transfer model, the change characteristics of temperature and heat flux density at both cold end and hot end of the semiconductor are studied. According to different driving conditions and environmental conditions, the regulation of energy consumption of auxiliary cooling system is clarified. The result shows that, the energy consumption of the semiconductor auxiliary cooling system increases with the increase of the human body heat dissipation slightly. The influence of environmental temperature change on the system energy consumption is relatively large. Especially, the speed threshold is the key factor affecting the system energy consumption. High speed threshold is better at high driving condition but the volume of the system needs to be larger. Low speed threshold can effectively improve the energy consumption in the urban working condition.