Special box for bulk cargo shipping operation, combined accessory and operation method

The invention relates to a special box for bulk cargo shipping operation, a combined accessory and an operation method. The special box comprises a box body, a small unloading door is arranged on one side of the box body and moves between an opening position and a closing position, and a wedge block sliding groove is formed in the position, above the small unloading door, of the box body; the rotating rod locking mechanism is arranged on the box body, a switch wedge block is arranged at the position, corresponding to the small discharging door, of the rotating rod locking mechanism, and the switch wedge block is used for being matched with the wedge block sliding groove to control the small discharging door; when the small discharging door is located at the closing position, the opening and closing wedge block is vertically inserted into the wedge block sliding groove in a penetrating mode to close the small discharging door. When the small discharging door is located at the opening position, the opening and