The invention provides a safe driving method and system based on an ADAS module. The method comprises the steps that S1, the ADAS module recognizes the license plate number of a preceding vehicle; S2, the ADAS module transmits license plate information data to a controller module for processing; S3, the controller module has an access to a background server after processing the license plate information data and then inquires state information of the vehicle; S4, according to set judgment conditions, the controller module conducts comparison and chooses subtitle alarm or voice alarm; and S5, a driver judges whether the preceding vehicle is dangerous or not according to early warning information. The system comprises the ADAS module, a communication module and the background server. By the adoption of the safe driving method and system provided by the invention, the driver can inquire the vehicle condition information, such as vehicle maintenance and potential hazards, driving years of a driver of the preceding vehicle and the number of traffic accidents, of the preceding vehicle when being far away from the preceding vehicle, and take collision avoidance measures as soon as possible according to the early warning conditions, the driver can get away from accident-prone vehicles and green hands, the probability of traffic accidents is decreased, and driving safety is guaranteed.