Flattening machine of package stacking machine

A flattening machine of a package stacking machine comprises a speed reducer, a driving shaft, rollers, chain wheels, motor support plates, buffer devices, rotating arm supports and a rack. The speed reducer drives the driving shaft through a chain; a drive chain wheel at one end of the driving shaft drives the roller on the front side of the rack to rotate, and a drive chain wheel at the other end drives the roller on the rear side of the rack to rotate; the roller on the rear side is a roller set composed of a plurality of small circular rollers; the roller on the front side is an independent larger roller; the buffer devices enable the front and rear rollers to ascend or descend to any height through the rotating arm supports. The driving shaft is driven by the speed reducer and drives the drive chain wheels to enable the rollers to move, and packaging bags passing from the position under the rack are flattened; by the front and rear rollers of different structures, the packaging bags can be conveyed out more flatly; by the buffer devices, the packaging bags of different shapes can pass through smoothly.