The invention discloses an electrolyte of a high-voltage fast-charging lithium ion battery and the lithium battery. The electrolyte comprises a non-aqueous organic solvent, an electrolyte salt and anadditive, and the mass percentages of the non-aqueous organic solvent, the electrolyte salt and the additive in the electrolyte are 65%-90%, 10%-20% and 0-15% respectively. The electrolyte can improvethe normal-temperature quick charge cycle performance, the high-temperature storage performance and the low-temperature discharge performance of the high-voltage battery at the same time. The lithiumion battery prepared by adopting the electrolyte has lower surface density, is beneficial to reducing the impedance of the lithium ion battery, is smoother in lithium ion migration, can effectively improve the rate charge-discharge performance, and obviously improves the low-temperature discharge performance at the same time; the electrolyte of the high-voltage fast-charging lithium ion battery has the relatively high charging cut-off voltage, the capacity of the lithium ion battery can be improved by about 15%, and energy density reduction caused by surface density reduction is made up; andcompared with a conventional battery, the lithium ion battery has wider tabs, so that the ohmic impedance of the lithium ion battery is effectively reduced to facilitate electron transmission.