Abstract: Electrokinetic transport near charged interfaces is a typical multi-physical, cross-scale phenomenon. The charging effects and electrokinetic transport phenomena at immiscible liquid-liquid interfaces have been studied for a century and have garnered increasing attention in recent years. These phenomena provide novel electrokinetic-based strategies for the active control of multiphase flow and mass transfer systems at micro/nano scales, such as physicochemical interface-induced self-propelled droplets and electric signal-modulated digital microfluidics. Compared to solid-liquid interfaces, liquid-liquid interfaces, as multiphase soft diffuse interfaces, possess characteristics such as finite thickness, easy mobility, ion adsorption capability, and ion permeability. Their electrokinetic transport behavior is linked to fields such as membrane science, electrochemistry, physical chemical hydrodynamics, and electro-coupled hydrodynamics, gradually forming an interdisciplinary field—electrokinetic multiphase hydrodynamics. From the perspective of interdisciplinary integration and historical development, this review will briefly outline the fundamental electrokinetic theory of the electrical double layer and the unique behaviors of soft diffuse interfaces at charged liquid-liquid interfaces. It will systematically summarize the fundamental mechanisms of electrokinetic transport in typical scenarios, covering aspects such as droplet electrophoresis in free space, multi-interface electrokinetic flows coupled with hydrodynamic interaction, and solid-wall wetting dynamics coupled with surface and interfacial interactions. The aim is to showcase the vast potential and broad prospects of this field in applied fundamental research, particularly in the combined regulation of multiphase flows and ion transport.