With the cross construction of power grid and pipe network, the dynamic DC interference and AC interference on oil and gas pipelines show a mixed development trend, which aggravates the pipeline corrosion rate. In order to separate and detect dynamic DC and AC interference on oil and gas pipelines, the spectrum characteristics of dynamic DC interference and AC interference in the mixed interference signal are extracted using FFT with different resolutions. Then, the dynamic DC interference is approximately treated as DC signal by using the combination of subsection aggregation approximation and FFT to realize the separation of dynamic DC interference and AC interference and the calculation of characteristic parameters. The test results show that the detection progress of dynamic DC interference and AC interference meets the expected requirements. The deviation between the original AC interference potential effective value and the AC interference potential measured after separation is not more than ± 2. 5‰, and the difference between the dynamic DC interference potential effective value and the dynamic DC interference potential effective value measured after separation is less than 1 mV (not more than ± 0. 5‰). The work provides data support for interference source troubleshooting and targeted pipeline corrosion protection