The present application relates to the technical field of lithium-ion batteries and, specifically, relates to an electrolyte and a lithium-ion battery containing the electrolyte. The electrolyte of the present application comprises an organic solvent, a lithium salt and an additive, wherein the additive contains a cyanosulfone compound and a lithium fluorophosphate compound. When the electrolyte contains both the cyanosulfone compound and the lithium fluorophosphate at the same time, the cyanosulfone compound will form a passive film on the surface of the electrode of a high-voltage battery, so as to effectively suppress reaction between the electrolyte and the electrode, further, the lithium fluorophosphate can effectively suppress the decomposition of the lithium salt and improve the film resistance of the electrode. Under the synergistic effect of the two, the cycle performance of the lithium-ion battery is greatly improved, and the storage performance of the electrolyte is also significantly improved.