Plate gantry straightening hydraulic for aerospace, ship, metallurgy and other fields of steel leveling, forming technology; The main machine is composed of movable cylinder head, movable gantry frame and fixed table; The main cylinder head can be left and right displacement on the gantry frame, gantry along the length of the table displacement, the displacement of two aspects of the plate without blind spot correction; The main cylinder head is provided with the micro downward function, so that the steel plate can be precisely corrected. A plurality of ejection cylinders are designed in the effective panel area of the work table, which is convenient to add a plug correction point pad to the plate and facilitate the lifting of the plate.