<p>Injecting supercritical CO₂ (scCO₂) into deep saline aquifers is a promising strategy for large-scale CO₂ emission mitigation. Although numerous studies have investigated scCO₂ migration and displacement in porous sandstones, the dynamic displacement characteristics and the evolution of displacement efficiency under varying differential pressures remain poorly understood. Furthermore, few studies have distinguished displacement efficiency between dynamic displacement and equilibrium capillary state, limiting the accurate prediction of field-scale scCO₂ storage efficiency. This study employs Nuclear Magnetic Resonance (NMR) and Magnetic Resonance Imaging (MRI) techniques to investigate the dynamic displacement of water by scCO₂ in porous sandstone under pressure differences ranging from 0.1 to 22&#xa0;MPa. Two experimental series were conducted, namely, (i) a single drainage displacement of water by scCO₂ under various pressure differentials, and (ii) a three-stage process involving scCO₂ injection, water imbibition, and scCO₂ re-injection. By integrating displacement data with pore-size distribution characteristics derived from mercury intrusion porosimetry, the capillary pressure curve of the sample was determined. The results reveal that dynamic displacement yields higher water saturation than the static capillary equilibrium state by approximately 20%–30%. Furthermore, the system exhibits strongly water-wet characteristics, where the non-wetting scCO₂ phase preferentially invades larger pores, while elevated pressure differentials facilitate water displacement from smaller pores. Notably, cyclic displacement significantly enhances scCO₂ displacement efficiency by 1.8%–9.3%, as evidenced by a reduction in water saturation during scCO₂ re-injection&#xa0;stage. These findings provide insights into the multiphase flow dynamics of scCO₂–water systems and offer a basis for optimizing CO₂ storage strategies.</p>