Abstract: Constructed wetlands, as a water treatment technology that provides both ecological benefits and pollutant removal, have been widely used for water pollution control and ecological restoration in China. In engineering practice and statistical studies, surface flow constructed wetlands (SFCWs) are often confused with lakes, landscape water bodies, and broadly defined human-made wetlands, leading to biases in conceptual understanding and statistical results. This study systematically reviews the concepts of wetlands and constructed wetlands, and analyzes the definition, technical characteristics, and engineering applications of SFCWs based on China’s current standards, engineering application cases, and the technical features of these systems. The results show that although SFCWs are morphologically similar to shallow water bodies, they are essentially constructed wetlands with clearly defined treatment targets, controllable hydraulic conditions, and pollutant reduction targets. Pollutant removal in these systems mainly depends on substrate adsorption, plant uptake, animal grazing and bioturbation, particle sedimentation, and microbial transformation, while treatment performance is controlled by hydraulic loading rate, water depth, flow regime, and hydraulic retention time. Compared with subsurface flow constructed wetlands, SFCWs have lower construction and operation costs, but they also have limitations such as lower pollutant loading per unit area, larger land requirements, insufficient treatment stability under low-temperature conditions, the formation of short-circuiting and dead zones, decomposition of plant residues, and sediment accumulation. Current engineering applications still face problems such as inconsistent statistical scopes, greater emphasis on construction than on operation and maintenance, insufficient evaluation of hydraulic efficiency, breeding of mosquitoes and flies in some areas, and inadequate attention to unpleasant odors and long-term operational performance. Therefore, it is recommended to further standardize the conceptual framework, distinguish broadly defined human-made wetlands from constructed wetlands, unify statistical scopes for engineering applications, strengthen hydraulic regulation and operation and maintenance, and improve the engineering evaluation system for SFCWs from a life-cycle perspective.