Using reflective near infrared sensor and voice record-reproducing assembly, the present article studies the voice anticollision-prompting device for backing an automobile. If there is a man or an object within a certain distance behind the backing automobile, part of the infrared signal will be reflected by the man or the object, and received by the photosensitive tube installed with a transmitting tube, and transformed to a similar frequency electric signal. The electric signal will be amplified, demodulated, and shaped by the circuit of module. After comparing and processing, the control signal will be output, which controls the work of voice record-reproducing assembly, and reminds the driver that there is a man or an object behind the backing automobile. With both the near infrared sensor and voice record-reproducing assembly being integrated, the distance-warning device has the advantages of low costs, simple wiring, strong anti-detonation ability, precise measuring, and working stability. It is suitable for being installed and used on the automobile.