The invention discloses a full-automatic box folding machine of a semi-packed box of a heat collector. The full-automatic box folding machine comprises a rack and a feed receiving plate, wherein a box folding mechanism is arranged at the bottom of the rack, gluing mechanisms are respectively installed on both sides of the box folding mechanism, a positioning mechanism is arranged below the box folding mechanism, a grabbing movement mechanism is arranged on the rack, and the feed receiving plate is close to the box folding mechanism. When the full-automatic box folding machine is started, a paper box board can be carried and placed on the feed receiving plate by the grabbing movement mechanism, the paper box board is pushed into the box folding mechanism under the action of the positioning mechanism, the paper box board can be folded by the box folding mechanism and are glued by the gluing mechanisms, and automatic box folding is completed under the action of the box folding mechanism. Only the whole pack of box boards are manually put on a tray, after the full-automatic box folding machine is started, the whole process of feeding, gluing, folding and discharging a single box board can be automatically completed, automatic continuous production can be realized, and manual intervention is not needed until the whole pack of box boards are completed. The capacity and the working efficiency are improved, and the quality stability is guaranteed, thereby effectively increasing production profits.