Abstract: Using mid-grade and low grade green tea as raw material, technology of extracting caffeine was studied in this paper.Combining acetic ether extraction after microwave infusing treatment to separate and extract caffeine, it showed that therewas a lot of merits such as short time processing, high efficiency, nothing poisonous left over the product and so on. It alsorevealed that the optimal conditions of processing were: the concentration of NaCl was 0.2% and extracted 3 times by aceticether whose volume was two times of the experimental solution and the extraction rate was 95.14%. The caffeine was pruifiedby sublimation method with a yield of 1.2%, whose purity was 98.2%. The analysis purified of UV-VIS confirmed that thisseparation technology had no harm on the chemical structure of caffeine.

Key words: Tea , Caffeine , Extraction technology