The finished green tea irradiated by 60Co γ-rays was used to study the effects of absorbed dose, dose rate, and the water content of tea on the degradation rate of bifenthrin. The doses of 3 kGy, 7 kGy, 10 kGy, 15 kGy, and 20kGy and the dose rates of 10 Gy•min−1, 30 Gy•min−1, and 50 Gy•min−1 were chosen. And the water contents of green tea were 5%, 8%, 10%, and 17%. The results show that the degradation rate of bifenthrin in green tea increases at first and then decreases with the increasing absorbed doses, and reaches the highest when the dose was 10 Gy. With the increasing dose rates, the degradation rate of bifenthrin plummets, and is relatively higher when the dose rate is 10Gy•min−1 in our experiment. There is a positive correlation between degradation rate of bifenthrin and water content of the green tea. Based on the practical situation, lower dose rate, higher water content and a 10 kGy absorbed dose are suggested to decrease the bifenthrin in green tea.Cited