The invention discloses a device and method for governing oil-water-well oil-string-casing channeling, and belongs to the technical field of oil extraction equipment. The device comprises a jacking cylinder, a jacking nut, a base cylinder and tension pieces; the jacking cylinder sleeves an oil-string casing, a first flange extending outwards is arranged at the upper end of the jacking cylinder, and an external thread is formed in the outer wall of the jacking cylinder; the jacking nut sleeves the jacking cylinder, and an internal thread matched with the external thread in the outer wall of thejacking cylinder is formed in the inner wall of the jacking nut; the base cylinder comprises a supporting section and a packing section which are sequentially connected from top to bottom; the packing section is located in annular space between a surface casing and the oil-string casing, clamping teeth capable of being clenched with the outer wall of the oil-string casing are arranged on the inner wall of the packing section, and the jacking cylinder can enter the supporting section; a second flange extending downwards is arranged at the connecting portion of the supporting section and the packing section; the first flange, the second flange and a surface casing head flange are fixed through the tension pieces; the first flange is also fixed to a large four-way lower flange.