An apparatus (01) configured for identifying numbers for layers having objects thereon within a container (02), the objects being accommodated in the container and arranged in layers. the apparatus comprising: an optical fiber sensor (10) configured for detecting presence or absence of the objects from layers within a detecting range; a support frame (20) configured for carrying the optical fiber sensor (10); a guide rail (60) configured for defining a moving direction of the support frame (20); a motor (40) and driving mechanism (30) configured for driving the optical fiber sensor to move along the guide rail; and a controller (50) connected with the optical fiber sensor (10) and the motor (40), wherein the controller (50) is at least configured for obtaining the numbers for the layers having objects thereon according to a moving distance of the support frame (20), in the case that the presence of the objects is detected by the optical fiber sensor (10). In the case of a smaller spacing between the layers in the container (02), the apparatus (01) can accurately obtain the number for the layer in which an object locates, so that a robot arm can take out the object placed at this layer directly. The object is a display panel.