The invention belongs to the technical field of lithium-ion batteries, in particular to a lithium-ion battery electrolyte and a lithium-ion battery. Three additives, namely an additive A, an additiveB and an additive C, are added in the in the electrolyte, wherein the additive A can improve the cycle performance of a high-nickel material battery and inhibit the battery from increasing internal resistance in high-temperature storage and cyclic processes, the charging and discharging efficiency of the battery in charging and discharging processes can be improved, and self-discharging is reduced; the additive B can form a thin and compact SEI membrane on a negative electrode interface, so that a high-nickel material has relatively low interface impedance when matching with a high-volume high-compaction negative electrode material, and lithium-ions are favorably diffused; the additive C can inhibit a high-nickel battery from producing too much gas so that a battery explosion-proof valveis sprung in the long-term storage process at high temperature, and meanwhile has positive influence on the cycle life of the battery; therefore, the electrolyte guarantees that the battery has a relatively good cyclic life, the internal resistance of the battery in the use process is reduced, and when the battery is used at high temperature, potential safety hazards, which appear as the explosion-proof valve is sprung, are avoided.