Abstract: In response to the problems of difficult signal sampling, severe phase to phase interference, and insufficient detection accuracy in the live detection of zinc oxide arrester, an integrated leakage current detection method is studied. By designing a live detection sampling circuit and using synchronous sampling technology to obtain leakage current signals. By using three-phase digital phase shifting and interference angle dynamic compensation algorithm, the capacitance coupling interference between phases is effectively suppressed. Separate the fundamental component of resistive current by using windowed interpolation FFT algorithm. Through comparative experiments, it has been proven that the new detection method has higher accuracy in detecting results. The synthesized waveform of the detection results is consistent with the actual waveform of the leakage current, and the anti-interference ability is significantly enhanced. This provides a reliable technical means for the state evaluation of integrated zinc oxide lightning arresters.