Abstract: AC/DC voltages of pipe/soil greatly fluctuate when dynamic stray current interferes on pipeline. And it will be difficult to accurately locate the interference sources if conventional test station is used to measure the AC/DC voltages on pipeline. Synchronous monitoring method is presented. Memory stray current meter is used to measure the voltage values from different test stations at the same time, and the changing curve of voltage corresponding to time is set up. Based on the curve, comprehensive comparison on the instantaneous and mean voltage values at the same time is carried out so as to locate the interference sources. Accurate location on the interference sources can provide a fundamental to determine the current drainage position. Application cases in Dagang-Zhaozhuang Refined Pipeline for AC interference sources and Qinhuangdao-Beijing Crude Oil Pipeline for DC interference sources are given, and points for attention in the method application are presented.