Abstract: At present, the multiphase flow technology is applied increasingly in oil and gas mixed transportation system.However, the safety problems of multiphase pipeline are much more complicated than that of single-phase pipeline. Acousticsensing technology has the advantages of wide frequency range, long propagation distance and easy identification, and it isapplied to the two-phase flow pipeline with multiphase medium. Based on the variation of the maximum mean value and themaximum mean square value of the dynamic pressure signal before and after the leakage, the influence of the flow pattern, flow rate, leakage direction and leakage aperture on the leakage signal can be judged. Further, through theoretical analysis, the model of the relationship between the fluctuation amplitude of dynamic pressure and the gas-liquid flow during thestable flow of smooth stratified flow, wavy stratified flow and slug flow was established, which could be used to determinethe background noise amplitude fluctuation of steady flow under each flow pattern, laying a foundation for the realization ofacoustic leakage detection technology for gas-liquid two-phase flow pipeline.