<p>High-energy consumption has long been a major limitation of electro-osmosis in soft clay, largely due to the significant contribution of interfacial resistance, particularly concentration polarisation resistance, at the electrode–soil interface. Continuous supply leads to the accumulation of electrochemical reaction products (H⁺ and OH⁻) near the electrodes, which elevates interfacial resistance, and reduces energy efficiency over time. This study proposes a non-symmetric polarity&#xa0;reversal (NSPR) approach designed from the perspective of interfacial resistance. Unlike conventional reversal with equal voltage and duration in both directions, NSPR uses the reversal phase to relieve polarisation, and limit interfacial potential loss. Laboratory tests varied reversal voltage and time, measuring drainage, interfacial resistance, current, and energy use. NSPR suppressed the growth of interfacial resistance and sustained higher current. The best case, with a reversal voltage of 6 V and a reversal duration of 4 min, achieved the highest drainage. Relative to symmetric reversal, cumulative drainage rose by 169%. Compared with continuous DC supply, this case reduced total energy consumption by 24.3% and the energy coefficient by 52.8%, while increasing the cumulative drainage volume by 60%. Mechanistically, NSPR exchanges the electrode reactions to consume accumulated H⁺ and OH⁻ near the interfaces and moderates early-stage drainage, which helps prevent cracking and electrode–soil detachment. A real-time diagnostic based on the intra-cycle trend of interfacial resistance is introduced, together with a reversal-intensity metric that quantifies the combined effects of reversal voltage and time. The findings provide mechanistic insight and practical guidance for energy-efficient electro-osmosis in soft ground improvement.</p>