In this study, the dynamic analysis of Pipeline Inspection Gauge (PIG) flow control innatural gas and liquid pipeline is considered. The basic equations are differential formsof the mass and linear momentum for compressible liquid and gas flows. The fluid flowequations and a linear momentum equation of the PIG are solved simultaneously using anappropriate numerical method. Solution of these nonlinear equations results in a set ofdiagrams for the variations of the fluid pressure, mass flow rate of the gas and the PIGvelocity through the pipeline. Comparing the results of mathematical model for the PIGwith the established experimental data in a segment of Ahwaz gas pipeline shows a goodagreement between the measurements and computations.