Cargo compartment safety supporting device, operation method and dump truck

The invention discloses a cargo compartment safety supporting device, an operation method and a dump truck, the cargo compartment safety supporting device comprises a base, a supporting rod, a bracket, a pin shaft, a positioning screw, a locking nut, a locking pin, a multi-hole locking mechanism and a plurality of key locks, the supporting rod is hinged to the base through the pin shaft, and the supporting rod can rotate around the pin shaft; after the supporting rod is overturned to a certain angle, the limiting face makes contact with the positioning screw to limit the supporting rod to continue overturning, the locking pin is inserted into the locking pin hole, and the multi-hole locking mechanism and the key lock are connected in a hung mode; the locking pin limits the reverse rotation of the supporting rod; the elongation of the positioning screw depends on the overturning angle of the supporting rod; the cargo compartment safety supporting device is installed on the side face of the vehicle frame and us