Charged two-dimensional nanosheet-assembled membranes exhibit considerable promise for sustainable osmotic energy harvesting. However, conventional techniques such as filtration often lead to uncontrollable nanostructure geometries, which can substantially diminish the ion regulation efficiency of the membranes. In this work, we developed a novel microfluidic-mediated oriented nanoengineering approach for the continuous construction of highly oriented bacterial cellulose nanofiber (BCNF)/MXene composite membranes. Compared to traditional filtration membranes, the orientation angle distribution narrows from 0-80° to 0-20°. Moreover, these membranes achieved the maximum power density of 23.7 W/m