Abstract: In order to solve the problem that it is difficult to apply the existing leakage detection mechanism of singlephase pipelines with no consideration to the influence of flow patterns to the multiphase pipelines, the theoretical study and test analysis were conducted. Herein, the influence mechanism of flow patterns on the acoustic signal of pipeline leakage was studied, and in conjunction with the multiphase flow acoustic leakage detection test, the acoustic signals before and after pipeline leakage under different flow patterns were collected, of which the characteristics were also analyzed with the signal processing methods such as the Power Spectral Density (PSD) analysis, the Probability Density Function (PDF) analysis and the amplitude spectrum analysis. The results show that the flow pattern has a great influence on the leakage characteristics of multiphase pipelines, and the flow background noise and leakage sound source of pipelines have variable characteristics under different flow patterns. Generally, this study is a basic research on the acoustic leakage detection of multiphase pipelines, and it can provide theoretical support for the subsequent research on the generation and propagation mechanism of pipeline leakage acoustic waves under different flow patterns.