Abstract: It is the basis of technological calculations for two-phase flow in oil and gas pipelines to predict the slug flowing characteristic parameters. Many research results show that equilibrium liquid film simplified model applied to determine the characteristic parameters of slug flow is not valid by comparing experimental data. According to the basic hydrodynamic equations of two-phase flow, a coupling analysis approach to calculating the characteristic parameters of liquid film zone based on the slug tail velocity-hold-up profile is presented in this article. A series of correlations in consideration of the effects of fluid physical properties, pipe inclined angle and pipe diameter are applied in the liquid slug zone with a smaller statistical error and a relatively high accuracy, by comparing with TUFFP's data of TULSA and semi-empirical or semi-theoretical models available at present. In this paper, the modified model is applied in an oilfield spot case, but its effect should be further proved for lack of sufficient experimental data. Because theoretical derivation is strict and reliable, these formulas can be used in engineering calculations of field pipelines and theoretical researches of two-phase flow.