Nanofiltration and reverse osmosis technologies demonstrate remarkable advantages in the water treatment field by virtue of their precise separation performance and flexible adaptability. Among these technologies, ultra-low pressure nanofiltration/reverse osmosis membranes can drastically reduce operating energy consumption while efficiently retaining pollutants such as organic matter and divalent ions in water. They are suitable for low-pressure scenarios including advanced purification of municipal tap water and reuse of industrial wastewater, balancing treatment efficiency with cost control. On the other hand, reverse osmosis membranes dedicated to seawater desalination feature excellent contamination resistance and high desalination rates, enabling stable operation under harsh conditions of high salinity and high osmotic pressure. As a core technology addressing freshwater scarcity in coastal areas and islands, these membranes can directly convert seawater into freshwater that meets drinking or industrial standards, facilitating the recycling and efficient development of water resources.