The invention provides an automatic unlocking device and method of an automotive 
seat belt and a vehicle. The automatic unlocking device of the automotive 
seat belt comprises a sensor, a 
signal controller and an automatic unlocking device body. The sensor is mounted on a vehicle 
assembly and is used for detecting opening and closing states of vehicle 
doors and wheel speed and obtaining information of the opening and closing states of vehicle 
doors and information of the wheel speed. The 
signal controller is connected with the sensor and is used for sending a 
control signal according to the information of the opening and closing states of vehicle 
doors and the information of the wheel speed. The automatic unlocking device body is mounted in a buckle shell of a seat bolt buckle, is connected with the 
signal controller, and is used for receiving the 
control signal and controlling the automotive 
seat belt to be unlocked automatically according to the 
control signal. By the aid of the automatic unlocking device, automatic unlocking of the automotive seat belt is realized, driving security is guaranteed while operation load of a driver and passengers is reduced, frequency for the driver and the passengers fastening the automotive seat belt is increased, and security of 
vehicle driving is improved greatly.