The utility model discloses a tetra-split type subspan oscillation prevention power transmission line spacer. The spacer comprises a quadrilateral frame and a wire clamp. The wire clamp comprises two long wire clamps and two short wire clamps. The long wire clamps and the short wire clamps are successively alternatively arranged at the four point angles of the quadrilateral frame, the four point angles of the quadrilateral frame are respectively connected with the front ends of the wire clamps, the rear ends of the wire clamps are provided with clamp holes, and the inner walls of the clamp holes are provided with rubber gaskets; and the center lines of the two wire clamps arranged at the opposite angles of the quadrilateral frame are disposed at the extending line of the diagonal line corresponding to the opposite angles. According to the utility model, the long wire clamps and the short wire clamps are successively alternatively arranged at the four point angles of the quadrilateral frame, and the intervals between split leads respectively fixed in the clamp holes of the long wire clamps and the short wire clamps are increased through the long wire clamps and the short wire clamps with different lengths, such that the influence exerted by subspan oscillation on operation safety of a high-voltage-grade power transmission line is reduced, and safe and stable operation of an electric power system is ensured.