The invention discloses a lifting device for welding sealing covers in a big soft infusion bag production line, comprising a driving mechanism, an oscillating arm, a lifting slide shaft and a welding head of the sealing cover; wherein, an output end of the driving mechanism is connected with the oscillating arm, a lifting slide shaft is sheathed on a lifting base, the top of the lifting slide shaft is provided with the welding head of the sealing cover, and the bottom of the lifting slide shaft is connected with the oscillating arm through a connecting rod. The lifting device for the sealing cover welding in the big soft infusion bag production line of the invention has simple and compact structure, low cost and reliable use, and is not easy to be damaged.