The selenium content of tea was determined by atomic fluorescence spectrometry, and the factors influencing the extraction rate of selenium from tea were studied. The results show that the most important factors influencing the extraction of selenium from tea are the selenium content of tea and the dunking time. The selenium extracted from tea is almost organic selenium. The selenium content is of the most when dunked in water of (95±2)℃. And the selenium content of the first dunking was 4~7folds of that of the second dunking.