The invention discloses a synthesis technique for simultaneously obtaining difluoro oxalate lithium borate and di-oxalate lithium borate with outstanding performances, comprising the following steps: 1. reacting fluorinated compound, boracic compound, lithium-containing compound and oxalate-containing compound in a reaction medium at 100 DEG C with reaction pressure of 0.1-1MPa, wherein the mol ratio of lithium, fluorine, boron and oxalate ions is 5-9:5-9:2-3:3-4, and generating a reaction solution containing difluoro oxalate lithium borate and di-oxalate lithium borate; 2. carrying out initial separation on the difluoro oxalate lithium borate and di-oxalate lithium borate in the reaction solution, then carrying out further extraction separation by using organic solvent capable of extracting difluoro oxalate lithium borate or di-oxalate lithium borate; and 3. respectively carrying out recrystallization and vacuum drying to obtain the difluoro oxalate lithium borate and di-oxalate lithium borate of battery level. The invention is suitable for industrially producing two types of lithium salts with excellent performance used for lithium ion batteries.