The application discloses an air conditioner control system comprising a monitoring device and a host computer. The monitoring device comprises a microprocessor and a monitoring circuit which is connected to a communication line between an internal unit and an external unit of an air conditioner in series. The microprocessor is connected with the monitoring circuit and the host computer which includes a display module. According to the application, the monitoring device and the host computer are adopted to form the air conditioner control system, and running information of an air conditioner can be timely sent to the host computer for feedback and is displayed by the display module, such that closed loop control for the air conditioner is realized and a user can know actual running parameters of the air conditioner in a real-time manner. If the air conditioner breaks down, the user can rapidly determine fault reasons by searching abnormal actual running parameters. Therefore, the air conditioner control system, easy to implement and high in efficiency, helps to solve problems of the prior art.