Film blowing machine production 20% rolling bag folding device, the device installed in the film blowing machine, including frame, first guide roller and second guide rollers and the guide roller and the guide roller, the fifth guide roller, the sixth guide roller, a sliding triangular plug board, inserting plate angle control device. The first guide roller, the second guide roller, the third guide roller, the fourth guide roller, the fifth guide roller, the sixth guide roller, the sliding triangle inserting plate and the inserting plate elevation angle control device are all installed on the machine frame. Work, first guide roller from the film blowing mechanism to change the transmission direction connecting the second guide roller, film the second guide and connection installed sliding triangle inserting plate so that folding film, through the guide and the film extended horizontal connecting the four guide roller, the film extension levels are inversely connected in the direction of the guide roller, the film extended horizontal and vertical direction connecting the sixth guide roller. The utility model the film can be folded into eight layer, through the rolling bag making machine makes the sealing of garbage bag is easy to store and carry out, large volume and high.