Abstract: FFluoro L dopa ( 18 FDOPA) is synthesized from the starting material nitro vera traldehyde via multi step reaction by nucleophilic displacement combined with chiral catalytic phase transfer alkylation techniques and the enantiomeric purity of 18 FDOPA is determined by HPLC method using a chiral mobil phase and reversed phase C18 column. The results show that the total time of synthesis is less than 120 min, the total radiochemical yield from potassium 18 F fluoride is about 6.3 % with decay correction and the enantiomeric purity and radiochemical purity are high than 95 % and 99 %, respectively. The practical techniques are provided for the radiochemical synthesis and entiomeric purity determination of 18 FDOPA and other 18 Ffluoro L amino acids.