The invention discloses a packaging bag clamping device. The packaging bag clamping device comprises a base, and a pair of supporting portions which correspond to each other and protrude out of the surface of the base are arranged on the base. The supporting portions are provided with cavities with openings; first supports are fixedly connected with the cavities, and the first supports are of opening structures with hollow tops; and second supports are movably inserted in the first supports, and clamping portions are arranged on the tops of the second supports. The packaging bag clamping device has the beneficial effects that the structure is simple, use is convenient, and meanwhile, the length of the supports can be adjusted, so that the device can be suitable for sealing bags of different sizes.