The utility model discloses a negative pressure vacuum apparatus's seal structure, including left and right sides open -ended seal box to and set up at the qianmen and the back door of the seal box left and right sides, opening and closing of qianmen is controlled through qianmen jacking cylinder in the qianmen, the back door through back door jacking cylinder control the back door open close, four apex angles at qianmen and back door are provided with locking device. The utility model discloses a qianmen jacking cylinder and back door jacking cylinder are used for controlling opening and closing of qianmen and back door on vertical, locking device is then in that transversely general qianmen and back door and seal box compress tightly to realized the sealed of seal box, not only easy operation is sealed effectual moreover.