The present invention provides a living body identification device, a living body identification method and a living body authentication system. The living body identification device comprises an acquisition unit and a processing unit; the acquisition unit is configured for emitting light towards a characteristic position of the living body and receiving light reflected from the characteristic position, then converting the light into an electrical signal, and sending the electrical signal to the processing unit; the acquisition unit comprises at least one light source and a plurality of photosensitive elements which are disposed at intervals; the processing unit is configured for generating an image of the characteristic position according to the electrical signal, and processing the image of the characteristic position to eventually obtain the characteristic information of the characteristic position, the characteristic information being used for uniquely identifying the living body. The living body identification device can not only identify the living body more flexibly, but also identify the living body in both cases of contacting and not contacting the characteristic position of the living body.