Spiral wound nanofiltration membrane is a mainstream compact membrane element designed for industrial fine separation, featuring high filling density, stable interception precision and low energy consumption. It is specially applied in deep desalination, selective decolorization, impurity removal and low-temperature concentration of plant extracts, fermentation liquids and natural product solutions. Different from hollow fiber and tubular membranes, spiral wound nanofiltration realizes high-efficiency graded separation of small-molecule impurities and active ingredients through unique spiral flow channel design. With stable separation performance and easy industrial integration, it has become the preferred core equipment for high-precision refining of modern natural biological products.