Automotive air conditioning control system has been widely used in our daily life. With the help of the method of theoretical calculation and the principle of thermodynamics to establish a car air heat load balance equation, the traditional mode ignores practicability and operability. Modeling objects based on the car as considering object, this paper establishs a new heat load balance equation, and simplifies the solution to the original formula so that collects more data to reduce the disadvantages. According to air quality in China, it will increase calorific value part of taking a breath fresh air, ensure vehicle ride comfort.