The utility model discloses a saddle-shaped grading ring used for a 500kV-line 3850m-altitude 20mm ice zone. The saddle-shaped grading ring includes a ring body, and a left support and a right support, which are welded with the ring body and distributed symmetrically. The part between the ring body and two welding points of any support is saddle-shaped. The two sides of each saddle-shaped part are linear parts. The inclined angles of the linear parts at the two sides of the saddle-shaped parts are identical with a main inclined angle of matching V-shaped single-connection insulator strings. The saddle-shaped grading ring used for the 500kV-line 3850m-altitude 20mm ice zone is applicable to V-shaped single-connection insulator strings of a 500kV-line 3850m-altitude 20mm ice zone and capable of ensuring safe operation in an extra ice and snow load, effectively improving the voltage distribution close to wire root insulators and reducing visible corona, audible noises and radio interferences.