In the extreme case of a high-pressure gas well being completely evacuated, the method of displacement well killing is often used to gradually restore the pressure balance within the wellbore. However, due to the effect of liquid flooding, some of the well killing fluid can be carried to the wellhead by the shearing action of high-speed gas flows, resulting in a slower rate of pressure balance within the wellbore. In response to the aforementioned engineering challenges, an integrated expression model for displacement well killing parameters was built by analyzing the gas-liquid two-phase flow patterns in the wellbore under inverse contact conditions, and the reliability of the model's simulation results was verified through physical experiments. Subsequently, considering the diversity of sensitive factors, the constructed model was used to simulate and analyze the displacement well killing process under various conditions, including different densities, viscosities of well killing fluid, casing inner diameters, and well inclination angles. The results show these as follows. The higher the viscosity of the well killing fluid, the stronger the shearing action exerted by high-speed gas flows, which more readily triggers the liquid flooding effect during the displacement well killing process. The greater the density of the well killing fluid, the weaker the carrying action by high-speed gas flows, and the higher the threshold for triggering the liquid flooding effect during the displacement well killing process. The larger the casing inner diameter, the lower the flow velocity of the gas in the wellbore, and the weaker the shearing action on the well killing fluid. The greater the well inclination angle, the thicker the liquid film formed by the well killing fluid, and the larger the contact area with high-speed gas flows, which more readily triggers the liquid flooding effect during the displacement well killing process.