The invention discloses an automatic millimeter wave image target identification method and a device. The method comprises steps that (1), sub image blocks of a to-be-identified target millimeter wave image are acquired; (2), based on a trained convolutional neural network, target containing probability values of the sub image blocks are acquired; (3), based on the probability values, a probability cumulative graph of the to-be-identified target millimeter wave image is acquired; and (4), based on the probability cumulative graph, target marking is carried out so as to accomplish target identification of the to-be-identified target millimeter wave image. The invention further discloses an automatic millimeter wave image target identification device. The device and the method are advantaged in that the device and the method are suitable for automatic millimeter wave image target identification, the excellent target identification effect is realized, a problem that employing traditional manual design characteristics for the millimeter wave image can not realize the excellent detection effect in the prior art is solved, precise target positioning is realized, false alarms are reduced, safety check efficiency is improved, and manpower cost is reduced.