The graduation project's main task is to control auto air-conditioning system design, the system is the combination of ATmega16L microcontroller and a number of peripheral devices (such as ULN2003, SC16312, L9997ND) applications, combined with the control scheme achieved by the software program. The control system in treatment plants mainly in the following input: the temperature inside the signal, the vehicle outside temperature signals, signals the temperature of water temperature, fan feedback signals, mixed-signal throttle feedback, backlight signal, output device for VFD Vacuum fluorescent displays, control device is mainly on the control panel button, and the programme is based on speed, the temperature of the air-conditioning systems to intelligent control of the throttle motors and compressors work, making the temperature inside the set in accordance with Temperature in the body feel comfortable within the scope of, and through the throttle to control motor movement in the direction briefing, the proportion of hot and cold wind, automatic control, mandatory defrost, air circulation inside and outside the conversion and failure are shown this control system Can be achieved by the specific function. In this paper, automotive air-conditioning control system design, through this programme, detailed description of the structure of the control system, control system and a description of the hardware required to achieve the main circuit chips, the focus of the realization of the hardware circuit, is given to To achieve the specific function of the actual circuit. Then automatic air-conditioning system under the control of the programme, the software program is the subject of ideology, system integration MCU instructions to write software flow chart.