Abstract: The fermentation conditions of Candida parapsilosis (GPT-5-11) were optimized for the production of γ-aminobutyric acid by liquid fermentation experiments. The results showed that the optimum conditions were as follows: the optimal medium composition (g/L) was glucose 24.5, yeast 6.2, soy peptone 6.2, Twain 80 2ml, alcohol 4 ml, MgSO4?7H2O 0.2, MnSO4?4H2O 0.045, L-MSG12.5; concentration of L-MSG was 12 g/L; cultivating pHwas 6.5; and cultivating period was 48 h under 37℃. Under optimal conditions, γ-aminobutyric acid production reached 2.58 g/L.