In the process of fluid flow, sound field and flow field are inseparable. They have the characteristics of interaction. In order to better divide the leakage process of gas-liquid two-phase flow pipeline. Especially the generation mechanism of leakage sound source. In this paper, the leakage of horizontal gas-liquid two-phase pipeline is simulated based on ANSYS software. Firstly, the geometric model of pipeline leakage is simplified. Then, fluent dynamic grid technology and UDF programming are used to realize the process of pipeline leakage opening. And then complete the flow field simulation. Through the analysis of the parameters of the leakage flow field, the characteristics of the leakage sound source are obtained, which is verified by the theory. The time and location of the leakage source are obtained. Through numerical simulation, the parameters of leakage process are analyzed under three flow patterns: stratified smooth flow, stratified wave flow and slug flow. Compared with different flow patterns, the flow field of leakage opening process is different. Supplement the deficiency of the experiment in describing the flow field parameters. And then provide theoretical support for acoustic leak detection technology.