The invention discloses an AOD furnace movable trolley locking device and a using method. The AOD furnace movable trolley locking device comprises a movable frame, a top half part and a bottom half part. The top half part is installed on the movable frame. The bottom half part is fixed to the ground of a movable AOD furnace smelting station and is further fixed with foundation bolts. The top half part makes up-down vertical movement and is connected with the bottom half part through wedge-shaped locking block cavities and a trapezoidal locking block. The middle part and the two sides of a trolley body of the movably trolley are each provided with a trolley locking device body, and the trolley locking device bodies are installed vertically and horizontally. The AOD furnace movable trolley locking device has the advantages that the structure is simple, reasonable and compact, and the operation method is easy; double locking hydraulic cylinders are adopted, each wedge-shaped locking block achieves independent driving, a pressure sensor can operate the magnitude of tight locking force according to a preset value, operating is accurate and locking is evenly stressed; the wedge theory is adopted in the stressing of the wedge-shaped locking blocks and the trapezoidal locking block, transverse acting force is large and the trolley body can be effectively stabilized; and the trapezoidal locking block achieves lubricating connection with a shaft sleeve and can further rotate around the shaft sleeve, and thus the effect that the contact surfaces can be highly attached is guaranteed.