The OPP labeler is mainly applied to round bottles. It utilizes the rotary table to feed the label by vacuum and attaches the label completely onto the bottle with the outside pressing belt. It is impossible for the pressing belt to achieve rotary pressing on square or flat bottles. The label feeding tray of this labeler adopts mechanical connecting rod. When the label is too tight, the label feeding tray will be automatically released. If the label is too loose, the label feeding tray will be automatically tightened to maintain the tightness. In addition, there is a group of correctors during the feeding of labels for correcting the label height immediately so as to maintain stable height of labels.