Abstract:[Objective] To provide the basis for the activity of activated sludge, as an important index in activated sludge, adenosine triphosphate (ATP) is detected to study the activity of activated sludge in the research. [Methods] The research used the method of TCA and microwave to detect ATP in activated sludge. Influencing factors (such as the concentration of TCA, time of immerging in an ice bath, pH, frequency of microwave and treatment time with microwave) are also discussed. [Results] The optimal concentration of TCA in the activated sludge is 2.5% with the concentration of TCA of 1.0%?7.0%; during 2?60 min immerging time in an ice bath, the optimal time using ice bath is 10 min; the optimal pH of Tris-EDTA buffer is 7.5. The suitable conditions for the method of microwave are: 800 W and 15 s for microwave irradiation. [Conclusion] The method of TCA and microwave can detect ATP in activated sludge. However, compared with the method of microwave, the method of TCA can guarantee the integrity of ATP, thus, the method of TCA is more suitable for detecting ATP in activated sludge.