Objective: To determine the optimal conditions for chitinase production by Serratia marcescens XJ-01. Methods: The effects of culture conditions (e.g. carbon source, nitrogen source, temperature and pH) for chitinase production by Serratia marcescens XJ-01 were investigated by orthogonal experiment. Results: show that the optimal condition for producing chitinase is as follows: temperature of 32 ℃, pH 8.0, 5 g/L (NH4)2SO4 as the nitrogen source and 5 g/L colloidal chitin as the carbon source. Conclusions: The optimal conditions for chitinase production by Serratia marcescens were determined.