Abstract: Embodiments of this application provide a Bluetooth connection method, a system, and an electronic device. In the method, when a communication connection between an electronic device and a vehicle head unit is disconnected, the electronic device starts to scan a Bluetooth advertising signal. When a user carrying the electronic device is close to the vehicle head unit, the electronic device may obtain, through scanning, a Bluetooth advertising signal sent by the vehicle head unit. When obtaining, through scanning, the Bluetooth advertising signal sent by the vehicle head unit, the electronic device may start a vehicle manufacturer application when the vehicle manufacturer application is cleared by a system. The electronic device may reconnect to the vehicle head unit through Bluetooth by using the vehicle manufacturer application and a Bluetooth chip. Embodiments of this application can improve convenience of unlocking in a scenario in which a vehicle is insensibly unlocked.