The utility model discloses piston rising stem (RS. ) valve valve rod protection device belongs to the valve field, and the purpose provides a rising stem (RS. ) valve valve rod protection device of being convenient for observe the valve motion state. Including upper portion protective sheath and valve -stem nut, the upper portion protective sheath lies in the valve -stem nut top and can dismantle with valve -stem nut and be connected, be equipped with the through -hole in the protective sheath of upper portion, the through -hole is run through the upper end of upper portion protective sheath by the lower extreme of upper portion protective sheath, still include the piston rod, the piston rod sets up along the length direction of valve rod, and the piston rod lies in the through -hole, and one end can be dismantled with the valve rod top and be connected, and the other end exposes in the upper portion protective sheath. The utility model discloses a valve rod by under the circumstances of shroud, can observe the open -closed state of valve through the motion circumstances of observing the piston rod, it is more convenient to observe, more directly perceived.