The invention relates to the technical field of lithium ion batteries, and particularly discloses a high-temperature high-voltage safety lithium ion battery electrolyte and a lithium ion battery. Thelithium ion battery electrolyte comprises a lithium salt, a non-aqueous organic solvent and an additive, wherein the additive includes an isocyanate additive, a film forming additive and a fluorinatedflame-retardant additive. According to the lithium ion battery electrolyte, by adding the first type of the isocyanate additive and the second type of the film forming additive, a stable SEI film canbe formed on the surface of an electrode material, so that the ion conduction can be facilitated, and the decomposition of the electrolyte can be inhibited; and by adding the third type of the fluorinated flame-retardant additive, F atoms can form a film on an electrode interface, so that the intermolecular force can be reduced, the viscosity of the electrolyte can be reduced, and the conductivity of the electrolyte can be improved. All the components cooperate, so that the battery has good high-temperature storage performance, normal temperature cycling performance and high-temperature cycling performance under a high voltage, and does not have potential safety hazards.