Monitoring system for preventing drunk driving

The invention relates to the field of automobile monitoring, and in particular relates to a drunk driving preventing system. A monitoring device for preventing the drunk driving comprises an alcohol gas sensor, a controller, an indicating alarming device and an ignition control relay, wherein the alcohol gas sensor is mounted in an automobile and positioned in an automobile driving area; two input end ports of the controller are correspondingly connected to the alcohol gas sensor and a built-in automobile speed sensor of the automobile; a vehicle-mounted power supply in the automobile can supply power to the controller; a starting end port of the controller is connected to a starting signal end port of the automobile; the output end of the controller is connected to the indicating alarming device and the ignition control relay and can control the indicating alarming device and the ignition control relay; the ignition control relay is connected to an ignition switch of the automobile and can control the ignition switch. With the adoption of the system, the automobile running state can be forcibly monitored and related data can be recorded; the system can automatically work and does not affect people without drinking, so that the drunk driving can be monitored in real time; components of the automobile are utilized during the mounting of the system, thus the cost is low, the arrangement is convenient, and the possibility of drunk driving can be greatly reduced.