<p>The huge amount of oily wastewater generated by modern industry poses a significant threat to both human life and ecosystems, in which the oil–water mixture in the emulsified state is the most difficult to treat. In this review, starting from the stabilization mechanism of emulsion, commonly used superwetting surface modification techniques in the field of oil–water separation were summarized from the perspective of material preparation. Subsequently, the demulsification strengthening methods for superwetting materials in current research were sorted, and advantages and shortcomings of these techniques were analyzed from the mechanism of demulsification. Finally, to address the most critical contamination issues in industrial applications, the principles of contamination generation were discussed in detail, including reversible “oil blocking” and irreversible “oil adhesion”. Recent research on anti-fouling modification techniques and long-term demulsification processes was introduced. Targeted selection of demulsification driving mechanism and synergistic utilization of multiple antifouling strategies for material modification are expected to yield superior and long-term demulsification performance. In the future, the demand and complexity of oily wastewater treatment will further increase, and the long-term superwetting emulsion separation technology has great application prospects. This review article will provide inspiration for researchers related to this field to solve more complex emulsion processing problems.</p>