The invention belongs to the technical field of lithium ion batteries and in particular relates to a non-aqueous electrolyte and a lithium ion battery. The invention provides the non-aqueous electrolyte which comprises a lithium salt and a flame-retardant additive; the flame-retardant additive comprises a polyfluorine compound or a mixture of the polyfluorine compound and a phosphorous-containing compound; the polyfluorine compound is one or more of polyfluoro chain carbonate, polyfluoro cyclic carbonate, polyfluoro chain ether and polyfluoro cyclic ether. A safety problem that the battery is short-circuited as the lithium ion battery is abused to easily form lithium dendrites is solved. Meanwhile, the invention also provides the lithium ion battery which comprises a lithium ion battery anode, a diaphragm, a cathode, an electrolyte and a battery housing. The electrolyte is the non-aqueous electrolyte.