The exceptional properties of boron nitride nanosheets (BNNSs) render them promising for diverse applications. Nevertheless, the obstacles of effectively readying them and their restricted ability to disperse in liquids are current constraints. In this study, a simple and efficient glucose-assisted mechanochemical exfoliation method was developed to achieve simultaneous exfoliation and functionalization of BNNSs. The BNNSs yield reached 87.5%, featuring grafted hydroxyl groups at the edges and well dispersed in water. Furthermore, the prepared BNNSs were dispersed into water and subsequently incorporated into a nanofiltration membrane using vacuum filtration. The vacuum filtration produced the BNNSs nanofiltration membrane with high water flux and flexibility interception rate due to its excellent dispersibility. The optimal interception rate of the BNNSs filter membrane for a 2 mg·ml