Natural gas wellhead flow and water cut data are essential for enabling real-time dynamic analysis and intelligent parameterization of gas wells. This study investigates the interaction between differential pressure and variables such as water cut, superficial velocity, temperature, and pressure within a centrifugal field, employing multiphase flow theory, finite element analysis (FEA), and laboratory data. It examines the relationship between the unsteady distribution of gas–liquid phases in the centrifugal field and the resulting static pressure profile. Key findings reveal that the gas superficial velocity is directly proportional to both axial differential pressure (ADP) and radial differential pressure (RDP), while inversely related to the differential pressure ratio. In the centrifugal field, the gas and liquid phases form a symmetrical distribution around the central axis, characterized by a “gas core + liquid ring” structure. The static pressure curve displays a distinct inflection at the gas–liquid interface, with higher pressure within the liquid phase and lower pressure in the gas phase, consistent with established principles. The RDP, a consequence of this organized gas–liquid distribution, reflects the cross-sectional water cut, and an inverse water cut measurement model demonstrates an impressive prediction accuracy of 97.2 %. Additionally, the gas–liquid two-phase friction coefficient is rederived from the gas friction multiplier, incorporating the effects of temperature and pressure on gas density. Ultimately, a novel gas–liquid two-phase flow measurement model for high gas–liquid ratios is developed, achieving an average relative error of just 7.18 %. This model satisfies the rigorous accuracy requirements for water cut monitoring at gas wellheads and offers critical theoretical support for the measurement of multiphase flow.