The invention discloses a lithium ion battery electrolyte. The electrolyte comprises a non-aqueous organic solvent, a lithium salt, a film formation agent and additives, wherein four additives of fluorobenzonitrile, fluorobenzene, an oxalic acid and phosphoric acid lithium salt and a fluorotrioxophosphate lithium salt are simultaneously added into the lithium ion battery electrolyte, a synergistic effect will be generated by simultaneously using the additives, so that the ternary positive electrode material has advantages of excellent cycle property, high-temperature storage performance, low-temperature discharge performance, safety and the like under a high-voltage (4.3-4.5V) condition, and the problem that the cycle property, the high-temperature performance and the low-temperature performance of a high-voltage ternary battery electrolyte in the prior art cannot be simultaneously compatible is solved very well.