Abstract: The domestic C-11 multifunction module was used to establish a simple, rapid, efficient synthetic technology for the fully automated synthesis of¹¹C-acetate. Methyl magnesium bromide Grignard (0.1 mL of 1.5 mol/L) was used as a precursor to react with the ¹¹C-CO₂ in the Loop ring to produce intermediate acetyl bromide. The intermediate was first hydrolysis by acetic, and then purified, elution, and hydrochloric with acid. Then, the unreacted ¹¹C-CO₂ was removed by nitrogen. Finally, the product was neutralized with sodium phosphate and purified with sterile filtration membrane. The total synthesis time was about 10 minutes. The synthesis yield of ¹¹C-acetate was (58.5±6.7)% (decay corrected), and the radiochemical purity was more than 99%. The residual solvents were analyzed by gas chromatography. Analysis results indicated that concentration of the acetonitrile and acetone were (0.007±0.002)% and (0.005±0.002)%, respectively. The whole synthesis process was automatically completed, and the operation was simple and flexible with high synthesis efficiency and radiochemical purity, it was suitable for clinical performance of PET.