The invention discloses a steel wire twisting device capable of closing a sternal incision. The steel wire twisting device comprises a base and a handle, a shaft hole is formed in the base, the handle is provided with a twisting shaft which is inserted into the shaft hole from the top end of the shaft hole and can rotate in the shaft hole, a partition ridge in the axial direction is arranged on the twisting shaft, steel wire grooves are formed in the portions, on the two sides of the partition ridge, of the twisting shaft respectively, an observation window is formed in the lower end of the shaft hole of the base by forming a transverse through hole, a pressure head is formed on the portion, below the observation window, of the base, a steel wire gathering via hole is formed in the portion, under the shaft hole, of the pressure head, and a tensioning mechanism capable of tensioning a steel wire is arranged on the portion, above the twisting shaft, of the handle. When the steel wire twisting device is used, after the steel wire winds around a sternum, the tensioning mechanism is twisted till the steel wire is completely tightened to make the axis of a twisting device perpendicular to the sternum; one hand holds the base fixedly, and the other hand unidirectionally rotates the handle to make the steel wire mutually winded around and twisted tightly in the same direction till the steel wire twisting part is twisted off at the observation window. According to the steel wire twisting device capable of closing the sternal incision, the steel wire can be prevented from being twisted off during operation, and the risk that the steel wire cuts the sternum or is snapped after operation is reduced.