Highly-permeable nanofiltration membranes are fabricated via the facile approach. Ultrathin cellulose nanofiber membrane is utilized as the intermediate layer. The 77.4 nm-thick membrane has the molecular weight cut-off of 824 g mol−1. The 77.4 nm-thick membrane has the pure water flux of up to 32.7 l m−2 h−1 bar−1. The membranes have a great potential application in fast water purification.