With the principle of chromogenic reaction,the paper studied the colorimetric method to determine γ-aminobutyric acid produced from glutamate in the presence of L-Glutamate decarboxylase.The optimum conditions for the determination of γ-aminobutyric acid were: enzymatic reaction liquid 1ml,Na2CO3(mol/L)0.2 mL,sodium tetraborate(0.01 mol/L,pH9.18) 1 mL,6% phenol 1 mL and then add 7.5% NaClO 5 mL.Placed the liquid in the boiling water for 10min and then in the ice for 5min.Added 2.0 mL 60% Alcohol to the liqu...