The fermentation condition of a recombinant strain to produce chitinase in Pichia pastoris was studied in this paper.By the shaking flask,the influences of inducing time, pH,methanol,oleic acid on the expression of chitinase were investigated.Results showed that the highest productivity of chitinase was obtained when induced for 108 hours.The expression of chitinase was repressed when pH was lower than 5.5 and the optimum condition was pH 5.5～6.0.The optimum concentration of methanol was 1%.The protein expression can be improved greatly when added 0.05% oleic acid.On the basis of these,the recipe of fermentation medium was optimized through orthogonal experimental design.The optimal conditions were found and the amount of protein expression reached 171.99mg/L,chitinase activity 49.58U/mL under the conditions.