A membrane decorated with fluorescent dyes has a greatpotential in detection and removal of contaminant from wastewater. However,traditional fluorescent dyes suffer from the aggregation-caused quenching effect,which could compromise their sensing efficiency. Here, a new “cellulose spacer”strategy is developed to conquer this challenge. Specifically, the nanocellulosehas a hydrogen bond interaction with hydroxyl-containing coumarin, whichserves as a spacer that prevented the π−π stacking of coumarin. In such amanner, a fluorescent cellulose membrane with anti-aggregation-causedquenching is obtained. As a demonstration of as-developed materials, thefluorescent cellulose membrane is used for mercury ion recognition andremoval, and the membrane shows great sensing and adsorption performance.Moreover, excellent cytocompatibility of the membrane is verified by cellproliferation of live/dead viability assays. This fabrication method is expected toprovide a new concept for the construction of fluorescent and biocompatible membranes for a large variety of relevantapplications.