The invention discloses a full-automatic paper box packaging machine. The full-automatic paper box packaging machine comprises a rack and further comprises a feeding mechanism, a lifting table, a boxforming mechanism, a box pressing mechanism and a box sealing mechanism, all of which are sequentially arranged on the rack from bottom to top. The feeding mechanism is used for conveying a paper boxto the lifting table. The lifting table can ascend and descend in the vertical direction, and in the vertical lifting process of the lifting table, the paper box is conveyed to the box forming mechanism, the box pressing mechanism and the box sealing mechanism from the feeding mechanism. The box forming mechanism is used for clamping the paper box and applying pressure to the paper box so that thepaper box can be extruded and formed. The box pressing mechanism is used for sequentially pressing leaves the same with the paper box in size. The box sealing mechanism is provided with adhesive tape, the box sealing mechanism is used for pressing the adhesive tape towards the leaves the same with the paper box in size so that the paper box can be sealed through the adhesive tape, and packaging is finished. Through cooperative work of the feeding mechanism, the lifting table, the box forming mechanism, the box pressing mechanism and the box sealing mechanism, the full-automatic paper box packaging process is achieved, the structure is simple, operation is convenient, and the packaging efficiency is improved.