An ultrafine powder tinning structure is characterized in that a storage box is arranged on each of both sides of an operation box, a seal box door is arranged on each storage box, and a gate sealing structure is arranged between each storage box and the operation box. Each gate sealing structure comprises an air cylinder, a gate sealing cavity, a gate frame, a gate board and a pulley locking structure, wherein the air cylinders are arranged at the upper ends of the sealing structures and drive the gate boards to lift in the gate sealing cavities, and a sealing strip is arranged on the edge of each gate sealing structure. The operation box is in connection with a feeding tank through a feeding pipe. A plurality of butterfly valves of the feeding tank are arranged on the feeding pipe. The operation box is in connection with a blanking tank through a discharge pipe, and a plurality of butterfly valves of the blanking tank are arranged on the discharge pipe. Oxygen controlling instruments, operation openings and observation windows are arranged on the operation box and storage boxes. A pair of operation gloves is connected on each operation opening in a sealed mode. The feeding tank, the blanking tank, the operation box, the gate sealing structures and the storage boxes are respectively provided with an air inlet valve or/and a discharge valve. The problems that fire is easily caught in an existing tinning structure and the like are solved, and sealing is tight.