Abstract: There are increasing new phenomena and new problems that cannot be explained by the common water quality parameters and theories or be solved by the available technologies in the researches and engineering practices of high-standard wastewater treatment. To establish systematic principles and methods for investigating water quality and building scientific and effective wastewater treatment risk management and safety assurance management systems, the characteristics of wastewater and the corresponding essential problems were evaluated in high-standard wastewater treatment, and a new concept of 'water feature' was proposed to support the development of wastewater treatment technologies and processes. Water Feature refers to the concentration, composition, safety, and stability of pollutants in wastewater, as well as their temporal and spatial fluctuation, such that it covers the quantitative, temporal, and spatial dimensions. The assessment of water feature should be conducted based on the evolution methodologies of quantitative concentration, compositional characteristics, toxicological effects, and potential transformation of pollutants. The engineering practice cases suggest that the research of water feature can help to improve the risk assessment, treatability prediction, treatment process design and optimization in the high-standard wastewater treatment. The study of water feature can significantly improve the system of risk management and safety guarantee for wastewater treatment. Thus, it is necessary to investigate the systematic methodology of water feature deeply and constituently, as well as its relationship with treatment technology optimization, risk control and management.