The invention discloses a lithium metal anode protection method improving lithium utilization efficiency, and relates to the field of lithium batteries. In a lithium battery, lithium metal is deposited on a current collector as a battery anode, and a high molecular polymer is added as an additive to an ester electrolyte. In the present application, the high molecular polymer is prepared by a polymerization reaction of monomer A being acrylonitrile or derivatives thereof, monomer B being perfluoroalkyl ethyl methacrylate or derivatives thereof, and monomer C being alkyl alcohol diacrylate or derivatives thereof. Due to the negative charge on the surface of lithium metal, the —CN and —CF