The invention discloses an automobile automatic brake device and method. The automobile automatic brake device comprises a master control module and further comprises an image recognition module, a laser ranging module, a voice playing module, a vehicle speed measurement module, an automobile brake mechanism and a storage module which are connected with the master control module. The image recognition module collects the size of an obstacle in front of an automobile; the laser ranging module collects the distance between the obstacle in front of the automobile and the automobile; the vehicle speed measurement module collects the vehicle speed of the automobile at the current moment; the master control module controls the automobile brake mechanism for deceleration or emergency braking according to the data collected by the image recognition module, the laser measurement module and the vehicle speed measurement module; and meanwhile, the master control module drives the voice playing module to broadcast the action of the automobile brake mechanism. By adoption of the automobile automatic brake device and method, the defect existing in the prior art is overcome, and rapid and timely vehicle speed automatic control is achieved.