The invention provides a medium-
voltage water-tree-retardant crosslinked
polyethylene cable material and a preparation method thereof and belongs to the technical field of wire cable materials and preparation of the wire cable materials. The medium-
voltage water-tree-retardant crosslinked
polyethylene cable material is prepared from raw materials as follows: 60-75 parts of
polyolefin composite resin, 15-25 parts of a
polyethylene silane-
grafting material, 5-10 parts of water-tree-retardant composite catalytic master batch and 2-5 parts of a cross-linking agent. The
polyolefin composite resin comprises raw materials as follows: 60-80 parts of low-density polyethylene and 20-40 parts of
ethylene vinyl acetate copolymer; the water-tree-retardant composite catalytic master batch comprises raw materials as follows: 70-80 parts of low-density polyethylene, 3-5 parts of a catalyst, 10-15 parts of a nucleating agent, 2-5 parts of an
antioxidant, 0.1-0.2 parts of a crosslinking agent and 3-5 parts of an assistant crosslinking agent. Formation of a water tree is delayed, surrounding water can be dispersed to a certain extent, formation of the water tree can be effectively inhibited, the overall
physical property of the material is improved, and the material has excellent mechanical and physical properties and is environment-friendly.