To study the hydrolysis activity of chitosanase, in this report, the coding sequence of chitosanse from Bacillus amyloliquefaciens HZ-1510 was cloned, and glutathione S-transferase (GST) fused-chitosanase was expressed and purified from Escherichia coli. Furthermore, we analysed the signal peptide, amino acid sequence and its three-dimensional structure. In the end, its chitosan hydrolysis activity was measured. The chitosanase gene consisted of an open reading frame of 837 bp which encoded a protein of 279 amino acids with predicted molecular weight of 31.45 ku. The protein contained a signal peptide with a cleavage site located between the 36th and 37th amino acids. The deduced amino acid sequence homology analysis of the chitosanase revealed that it belonged to GH46 family. The recombinant chitosanase has been purified to homogeneity by using only GST column chromatography. The optimal pH and temperature for the chitosan hydrolysis activity was 5.5 and 55°C, respectively. The enzyme activity was increased in the presence of Mn²⁺, Ca²⁺ and Mg²⁺. However, Fe³⁺, Ag⁺, Cu²⁺, Ba²⁺ and K⁺ could inhibit its activity. Furthermore, its activity could be increased in the presence of 0.1 mmol/L Zn²⁺ while it was inhibited by 2.0 mmol/L Zn²⁺. This study explored the optimal condition for hydrolytic activity of chitosanase and established a theoretical basis for its industrial application.