An automatic packaging machine for paper bags contains: a support platform, a rotation table, a stacking device, a displacement device, a packaging device, and a paper delivery device. The support platform includes multiple paper bags delivered thereon. The rotation table is configured to rotate the multiple paper bags at two opposite angles. The stacking device is configured to stack the multiple paper bags. The displacement device is mounted below the stacking device and is configured to deliver the multiple paper bags. The packaging device is connected on the displacement device and includes an entering platform, a press plate, and a glue sprayer. An inlet of the entering platform accommodates the press plate, and the glue sprayer is fixed on a predetermined position of the entering platform. The paper feeder is connected with the packaging device and is configured to deliver multiple packing papers onto the entering platform.