A method for preparing [18F]fallypride is disclosed, which comprises a first step for trapping a fluorine-18 to a polymer ion exchange cartridge; a second step for extraction of fluorine-18 by inputting low base concentrations: 5.0˜25 μL of 40% TBAHCO3 or K2.2.2./K2CO3 (5˜25 mg/0.5˜3.0 mg) as a phase-transfer catalyst in a mixture of alcohol/water (1.0/0.2 (v/v)) or alcohol as a solvent into the polymer ion exchange cartridge trapped by the fluorine-18; a third step for preparing a [18F]fallypride product by removing the solvent from the trapped fluorine-18, by inputting tosylate precursor in CH3CN as a solvent into a reactor and by reacting the same for 5˜35 minutes at 50˜120° C.; and a fourth step for preparing a pure [18F]fallypride by purifying the prepared [18F]fallypride product.