Abstract: Constructed wetlands represent a pollutant treatment technology that combines ecological benefits with pollution control and are widely used in China. Faced with the increasing demand for the purification of low-polluted water, such as agricultural drainage water, aquaculture effluents, polluted river water, and wastewater treatment plant effluents, as well as the treatment of pretreated rural wastewater, the number, overall size and individual size of constructed wetlands are increasing. Simultaneously, the technical level of constructed wetland is improving. However, in practice and statistical studies, surface flow constructed wetlands are often confused with lakes, landscape water bodies, and human-made wetlands. This confusion leads to misunderstandings in engineering and statistics. Surface flow constructed wetlands have a free flowing water surface and share some similarities with shallow water bodies, but they are essentially an artificial system subject to specific hydraulic conditions and designed to reduce pollution. We systematically reviews concepts related to wetlands and constructed wetlands, analyzes the definition, technical characteristics, and application status of surface flow constructed wetlands in combination with China's current standards system and practical engineering experience, and discusses problems of understanding in engineering practice, with the aim of providing references for related engineering research and applications.