In this study, sequential and simultaneous strategies of ultrasonication (ultrasonic bath) were investigated to enhance enzymatic production of N-acetyl glucosamine (GlcNAc) from chitin powder. For the sequential strategy, the ultrasonic caused chitin powder to a visible fleecy structure, and Scanning electron microscopy (SEM) showed the surface of the treated chitin had a fiber-like structure with a diameter of 50 200 nm. Moreover, Fourier transform infrared spectroscopy (FTIR), Element analysis (EA), and X-ray diffraction (XRD) revealed that the crystallinity of the chitin decreased with little deacetylation. The simultaneous strategy is a one-pot treatment and enzymatic hydrolysis of chitin. The concentration of GlcNAc was 2.65 g/L for the strategy, which was 1.18- and 5.0-fold higher than the sequential strategy (2.25 g/L) and untreated chitin (0.53 g/L), respectively. In conclusion, this approach provided an efficient and environmentally friendly method for reducing the crystallinity of chitin and enhancing its enzymatic hydrolysis.