The invention relates to the technical field of cable materials, and in particular relates to a flame-retardant thermoplastic polyurethane (TPU) cable sheathing material with an electromagnetic shielding function and a preparation method of the TPU cable sheathing material. The TPU cable sheathing material comprises the following raw materials in parts by weight: 25-85 parts of thermoplastic polyurethane, 5-45 parts of graphene, 5-35 parts of a flame retardant, 0.5-5 parts of a compatibilizer, and 0.02-0.1 part of an antioxidant. The TPU cable sheathing material provided by the invention has the electromagnetic shielding function, the shielding effectiveness (SE) value can reach 17-50 db, and the flame-retardant effect is excellent; and a single vertical burning test can reach a V0 level,the strength is high, the tensile strength can reach 25.2 MPa or more, the flexibility is good, the elongation at break is high and can reach 405% or more, and the mechanical properties are excellent.