A lithium ion battery electrolyte having good cyclic effects is disclosed. The electrolyte includes an organic solvent, a lithium salt and an additive. The additive includes a mono-isocyanate-group alkoxy silane compound and a film forming compound. The invention also discloses a lithium ion battery having good cyclic effects. The isocyanate-group alkoxy silane compound in the electrolyte is cheap, can be easily synthesized, and can be adopted as an effective water removing agent and be synergistic with the film forming compound at the same time. A stable SEI film can be formed on the surface of an electrode material, structure stability of cathode and anode materials in a charge-discharge cyclic process is increased, and electrolyte decomposition on electrode surfaces is avoided, and therefore the cyclic performance of the lithium ion battery under room-temperature and high-temperature conditions can be effectively improved.