Automobile external environment has important influence on the temperature distribution in the car. By using the numerical simulation method to analyze the influence of temperature, sunshine intensity and wind speed on the temperature distribution in the car based on FLUENT. And the transient flow condition and temperature field distribution of the vehicle are also analyzed by considering the coupling heat transfer between the turbulent flow and the seat. Calculation results show that: The surface of the car is a non-uniform temperature field with dynamic change, and the surface temperature gradient at different position is also distinct. The highest temperature position is located at the top of the car, and the temperature is gradually decreasing from top to bottom on sides of the car, and the larger of the environmental wind speed, the lower of the temperature. When the air conditioning is open at the moment, the flow field in the car is a complex turbulent, and the air temperature around the rear seat is lower than the temperature in the front row. This study can provide a theoretical basis for the optimization of automotive heat comfort.