Abstract: The influence factor on effiency of 18F-FDG is investigated with "2-pot"system to improve the yield of 18F-FDG. The synthesis effiency is leaded to low in evidence by water in synthesis system which it comes from K2. 2. 2 or acetonitrile of delivered tube. The lower impurity of recovery H218O also lead to low yield. The Triflate more than 15 mg can accord with operating requirement. The shortened synthesis time will benefit to EOS. The synthesis time shorten from 55 min to 44 min EOB can be increased from 50% to 65% by optimized synthesis time and controlled less water in synthesis.