This paper designs a intelligent car horn based on RFID(radio frequency identification and satellite navigation technology)。Horn gets automobile accurate geographic position information by satellite navigation chip and realize the communication between the cars by the RF module.When the other car's whistle is blowing ,the horn can accept the signal covering the vehicle speed and location information.What's more,it can quickly and accurately calculate the distance between vehicles to provide timely warning distance by sunplus. After testing,the horn is stable、reliable and adaptable, which can effectively prevent the closed windows that the driver did not hear the whistle sound caused by traffic accidents and improve traffic safety.