Reverse electrodialysis systems (REDs) based on nanochannels membrane has been widely researched for the high-performance osmotic energy harvesting. However, these nanochannels-based REDs are usually persistent and uncontrollable, which greatly prohibit the applications in versatile real-world. Herein, inspired by sensory neurons of mammals, the temperature-gated nanochannels was constructed by the functionalized Cladophora cellulose for controllable osmotic energy harvesting, in which the cationic Cladophora cellulose was grafting with poly(N-isopropylacrylamide) brushes via the atom-transfer radical polymerization. Based on this temperature-gated nanochannels, the output from osmotic energy harvesting systems could be regulated by alternating temperature switches in a reversible and stable manner. An output power density of 2.56 W/m⁻² was achieved by mixing artificial seawater and river water, which was the relatively higher value of the nanocellulose based materials. Overall, this strategy first develops cellulose-based nanochannels membrane with both intelligent response and osmotic energy collection functions, which anticipates wide potentials for controllable osmotic energy harvesting.