A threshing device with two-way pull wires and adjustable threshing clearance includes a tensioning mechanism, and several grid bars in clearance fit with side plates, wherein the tensioning mechanism is mounted on the several grid bars so that the grid bars can move in radial and tangential directions in the clearance; the tensioning mechanism includes a tangential tensioning device and a radial tensioning device, wherein the radial tensioning device is mounted in the radial direction of any one of the grid bars, so that the grid bars can move in the radial direction in the clearance; the tangential tensioning device is mounted in series in the tangential direction of the grid bars, so that the grid bars can move in the tangential direction in the clearance. Further disclosed is a combined harvester, which includes the threshing device with two-way pull wires and adjustable threshing clearance.