The invention discloses a film storage tensioner which comprises a rack. The upper ends and the lower ends of the two sides of the rack are each provided with a synchronous chain wheel. A synchronous chain is arranged between each synchronous chain wheel at the upper end of the same side and the corresponding synchronous chain wheel at the lower end of the same side. A mobile roller base is fixed to each of the synchronous chains on the two sides and provided with a mobile roller. The two sides of the rack are each provided with a vertical mobile roller slide shaft and a vertical cylinder. The mobile roller bases vertically slide on the mobile roller slide shafts. Each cylinder is internally provided with a piston. The pistons and the mobile roller bases are all magnetic. The tops and the bottoms of the cylinders are all provided with ventilation openings which are each connected with an air pipe. The top of the rack is provided with two passing rollers. According to the film storage tensioner, tension is adjusted through the cylinder, the large tension is provided, and the tension is quite convenient to adjust, and the problems appointed out in the background art are effectively solved.