Abstract: Nanocellulose(NCC) was prepared with cellulose pulp as raw material by using cellulase hydrolysis under sonication-assisted technology. Orthogonal test was used to optimize the preparation of NCC on the basis of single factor test. The structure and properties of NCC were analyzed and characterized by transmission electron microscope(TEM), X-ray diffraction(XRD), infrared spectroscopy(FT-IR), thermogravimetry(TG) and Zeta potential measurement. The results showed that the yield of 62.3% for NCC could be achieved when the cellulase dosage was 7%, reaction temperature was 50℃ and reaction time was 10 h. TEM image showed that the prepared NCC was short rod-like, which interacted with each other to form a web-like network. XRD results suggested that the crystal structure of NCC was cellulose I, and the crystallinity increased from 54.2% to 73%. FT-IR implied that the original chemical structure of NCC was not altered. TGA analysis indicated that the thermal stability of NCC was significantly improved compared with that of cellulose pulp. The Zeta potential test showed that NCC suspension had good dispersion stability in aqueous medium.