Abstract: For a gas condensate reservoir, hydrate inhibitor is added to prevent the generation of hydrate in transportation. In order to study the synergistic effect of different inhibitors, the actions of thermodynamic and kinetic inhibitors are analyzed, and the composite effects of kinetic inhibitors (poly N-vinyl pyrrolidone) and thermodynamic inhibitors (methanol, ethylene glycol) are studied through experiments. Particularly, the effect of kinetic inhibitors on alcohol system and the impact of systems with different alcohol contents on the inhibitory effect are studied emphatically. The impact of certain salinity water on inhibitory effect is selectively tested. The results show that poly N-vinyl pyrrolidone is compatible with alcohol system, and they interact with each other and can be compounded to effectively improve the inhibitory effect.