The invention provides a non-aqueous electrolyte for improving high-temperature electrochemical performance of a lithium ion battery as well as a lithium ion battery using the same. The non-aqueous electrolyte consists of asymmetric fluoro-sulfonyl imine lithium salt and an organic solvent, and has the characteristics of no corrosion to an aluminum foil, high thermal stability, high conductivity and the like. The non-aqueous electrolyte has electrochemical performance same as the existing LiPF6 and LiBF4 non-aqueous electrolytes at room temperature, and can remarkably improve electrochemical performance of the lithium ion battery using the non-aqueous electrolyte provided by the invention at high temperature.