A label to be attached on a plastic product formed in a mold and identifiable by a detecting device includes a soft circuit board, a protective layer and an adhesive layer. The soft circuit board has its outer surface provided with a radio frequency identifiable device (RFID). The protective layer is transparent, adhered on the outer surface of the soft circuit board for protecting and enabling RFID identified by a signal transmitted by a wireless detecting device. The adhering layer is made of a compound material and adhered on an inner layer for protecting the inner surface of the soft circuit board and the RFID as well. The label is attached on a plastic product during injecting molding process, widely usable for identifying an object affixed with the label by means of a detecting device.