Abstract: The influence factors on the yield of ~(18)F-FDG are investigated with "1-pot" system for improving the synthesis yield of ~(18)F-FDG again. The synthesis yield is affected by water which comes from delivered tube. The percent of hydrolyzation and the remain radioactivity on the reactor are affected by the temperature of nucleophilic reaction. The lost activity relates to the flow of N_2 in acetonitrile removed. The synthesis time can be shortened by basic hydrolyzing the mediates. The uncorrected synthesis yield(EOS) can be increased from 59% to 69.3% by optimizing synthesis time, removed remain water in deliver tube and QMA.