A gasliquid coupling excitation method was proposed to remove the pollutant from the inner wall of the pipeline by the pulsating fluid passing through the alternating gas path and the liquid path. The gasliquid pulse test system was designed and the dynamic model of highpressure gasliquid pulsed twophase flow was established. The simulation was carried out by using FLUENT module in ANSYS. Using the κ-ε twoequation turbulence model, the VOF model was selected for the gasliquid twophase flow model, and the SIMPLE algorithm was used to solve the twofluid control equations. The analyses of the curves and its cloud charts show that the pressure and its fluctuation of the mixed fluid increase with the increase of the initial mixing pressure of the gasliquid twophase flow. So, it provides a theoretical basis for the online cleaning of the complex hydraulic system and some theoretical basis of the new gasliquid coupling excitation is presented.