-The nutritional medium compositions required for chitosanase production by Streptomyces albus YT2 were optimized, and the strain was isolated from the coastal soil of Bohai Sea. Plackett-Burman design was applied to evaluate the effect of different medium compositions obtained by one-factor-at-a-time experiments. Glucose, peptone and MgSO 4 were found to influence the activity of chitosanase significantly. The steepest ascent method was employed to approach the experimental design space, followed by the use of Box-Behnken design and response surface methodology for further optimization of the chitosanase production. The medium composition for optimal production of chitosanase was as follows: 0.5 g/L chitosan, 55 g/L glucose, 1 g/L peptone, 2 g/L (NH 4 ) 2 SO 4 , 8 g/L urea, 1 g/L NH 4 Cl, 3 g/L KH 2 PO 4 , 1 g/L FeSO 4 ·7H 2 O, 2 g/L ZnSO 4 ·7H 2 O, 2 g/L CaCl 2 ·6H 2 O, 2 g/L MnSO 4 ·H 2 O and 2 g/L NaCl. The chitosanase production was found to increase from 11.56 U/mL to 39.87 U/mL, a 3.47-fold increase compared with that using the original medium.