The invention discloses a bag connecting mechanism for a full-automatic vacuum packaging machine. The full-automatic vacuum packaging machine comprises a vacuum and sealing device comprising a vacuum reciprocating mechanism and bag connecting mechanisms, wherein the vacuum reciprocating mechanism comprises a main box body capable of moving from side to side and side box bodies positioned and fixed on left and right sides of the main box body; and the main box body moves from side to side to be combined with one side box body so as to form a vacuum chamber and the vacuum chamber is combined with the other side box body so as to form an open packaging station. Two sets of the bag connecting mechanisms are respectively arranged on the front parts of two side surfaces of the main box body; each set of the bag connecting mechanism comprises a bag-connecting mounting plate, a first bag-connecting rod, a second bag-connecting rod and a pair of front tensioning wheels, wherein the bag-connecting mounting plate is fixed on the main box body; the first bag-connecting rod and the second bag-connecting rod are respectively rotatably arranged on the bag-connecting mounting plate and are connected through an opening/closing mechanism; the pair of front tensioning wheels are respectively arranged on the front surfaces of the first bag-connecting rod and the second bag-connecting rod; and thepair of front tensioning wheels approach each other or separate from each other along with the action of the opening/closing mechanism.