The invention discloses a low-friction, low-shrinkage, high-temperature-resistant, low-smoke and halogen-free sheath material for 5G optical cables and a preparation method thereof. The sheath material comprises the following raw materials in parts by mass: 15-30 parts of micro-crosslinked EVA master batch, 20-45 parts of an ethylene-vinyl acetate copolymer, 5-15 parts of linear low density polyethylene, 5-15 parts of modified polyphenyl ether, 10-20 parts of a hydrogenated styrene-butadiene block copolymer, 5-15 parts of a maleic acid glycoside graft, 0-100 parts of magnesium hydroxide, 25-50parts of a phosphorus-hydrogen flame retardant, 2-4 parts of an antioxidant, 3-6 parts of a lubricant and 1-3 parts of a smoke suppressant. According to the invention, the raw material formula is improved, particularly, the excellent characteristics of high and low temperature resistance, low shrinkage, high mechanical property, low dielectric property, self flame retardance, low friction coefficient, wear resistance and the like of the modified polyphenyl ether are fully utilized, by combining with the micro-crosslinked EVA master batch, the defects of large shrinkage and no temperature resistance of common low-smoke halogen-free materials are overcome, so that the sheath material disclosed by the invention is low in friction coefficient, low in shrinkage, resistant to high and low temperature and simple in preparation method.