The main reason of the pipeline corrosion and leakage is that water and solid particles are entrained in gas pipeline. Sensors of acoustic emission(AE) were placed on wall of the gas pipeline, the AE signals of gas pipeline which containing water droplets and solid particles are collected with different gas velocity, then the signals are used for multiscale wavelet analysis. It has been found that there are good correlation between the energy, characteristic frequency of AE signals and the gas velocity, particle type, particle quality in the gas pipeline. AE technology can be used for the fault detection of gas pipeline entraining water droplets and solid particles.