Nanocellulose (NC) has generated interest from the scientific community because of their biodegradability, and unique physiochemical characteristics. In this study, ionic liquid 1-butyl-3-methylimidazolium hydrogen sulfate BmimHSO4 combined with high ultrasonication is used to prepare NC from microcrystalline cellulose (MCC). The investigation by atomic force microscopy (AFM) revealed that the obtained NC had a rod-like shape with average particle diameter and length of 0.77 0.28μm, 2.11 0.65mμ respectively. Fourier transform infrared spectroscopy (FTIR) characterization exhibited that the prepared NC maintained the cellulose type I structure and the recovered IL (97%) composition remained intact as the pure IL. Therefore, it is expected to develop a green approach to produce nanocellulose with high quality using ILs. © Published under licence by IOP Publishing Ltd.