||The state-of-the-art thin film composite (TFC) membranes suffer from unsatisfactory desalination process efficiency, necessitating the development of a new membrane chemistry using novel materials. Here, we propose a core-shell structured, poly(acryloyl hydrazide)-grafted cellulose nanocrystal (fCNC) as a new building block material, which can be assembled into a reverse osmosis (RO) membrane via the layered interfacial polymerization technique. The high density amine functional groups provided by densely-packed fCNC produced a highly cross-linked selective layer network, which enables its application to a RO grade. Importantly, the fabricated membrane (fCNC-TFC) exhibited higher boron rejection than the commercial membrane, which was attributed to its boron capturing ability endowed by the abundant remaining functional groups. Moreover, fCNC-TFC exhibited better organic fouling resistance than the commercial membrane due to its excellent physical and chemical antifouling properties.