Abstract: Gas-liquid flow in a mobile pipeline gas-cap emptying process was numerically investigated based on dynamic multiphase simulation software OLGA. Simulation and experimental data in terms of flow rate, pressure and liquid holdup were compared under inlet pressures of 0.5, 0.7 and 0.9 MPa, respectively. The results show that the simulated emptying time has good agreement with experimental results under inlet pressure of 0.9 MPa, but it underestimates emptying time under other pressure conditions. Before the liquid forward reaches the test point, the simulated flow rate and liquid holdup results agree well with that of experiments, but the pressure value is overestimated. When the liquid forward passes the test point, the simulated parameters are all lower than that of experiments. The study confirms the applicability of OLGA software in the investigation of mobile pipeline gas-cap emptying processes.