Abstract: kinds of black teas,9 kinds of Chinese green tea and 18 kinds of Japanese green tea , 9 kinds of Oolong tea and9 other varieties of tea were used to repress against mutation of 3-amino-1,4-dimethyl-5H-pyrido- (4,3-b)-indole (Trp-P-1) and1-nitropyrene (1-NP) in the experiments. The results of antimutagenic activity suppression were carried out for comparisonanalysis on influencing factors according to the tea categories. The antimuagenic activity results of all assayed tea samples to resistTrp-P-1 were stronger than those of resist-1-NP. The average suppression on Trp-P-1 showed that for black tea it was about84.62%, for Oolong tea about 56.09%, for green tea about 48.34% and for 6 kinds of roasted green tea about 64.05%. The averagesuppression percentage of all tea samples on 1-NP was only 18.09%～24.03% and did not display the difference for differenttea categories significantly. During process the temperatures on the anti-mutation resulted great effect, such as 170 ℃ for 10 minuteson roasted green tea would cause suppression on Trp- P-1 mutation to increase 45.4%～70.2% and on 1-NP mutation to increase45.08%～108.9%.

Key words: tea, antimutagenicity, Trp-P-1, 1-NP