Abstract: In order to study the flow-pattern transition laws of gas-liquid two-phase flow and establish the gas-liquid hydraulic calculation model with high precision, three flow-pattern-prediction models, i.e. the general model, the modified Taitel-Dukler model and the slug characteristic analysis model, were introduced, and their application effects to predict the flow pattern of gas-liquid tow-phase flow were verified based on the experimental data from Shoham and Kokal. Then, based on these three flow-pattern-prediction models, the flow pattern prediction maps were plotted and compared with the experimental data. Finally, the characteristics of the three models were summarized. It is shown that the unified flow-pattern-prediction model and the model via slug characteristic analysis do better in the flow pattern prediction of gas-liquid two-phase flow and the unified model is more applicable to different situations. The research results provide the basis for selecting the flow pattern prediction algorithm used for the hydraulic calculation of gas-liquid two-phase flow.