Objective : To explore the association between serum γ-aminobutyric acid ( GABA) levels and the risk of developing type 2 diabetes( T2DM) ． Methods : 187 cases of T2DM patients attending the hospital were selected as the T2DM group，and 187 cases of non-T2DM population attending the same period of time were selected as the control group according to age ( ± 3 years) and gender 1 ∶ 1．On-site questionnaires and physical examination were conducted for the study subjects，and serum levels of GABA，Malondialdehyde ( MDA) and activities of superoxide dismutase ( SOD) and Glutathione peroxidase ( GSH-Px) were detected by using ELISA kits．The differences in the levels of GABA and oxidative stress indicators ( SOD，GSH-Px，MDA) between the two groups were compared， and the correlation between GABA and oxidative stress indicators was analyzed by Spearman's method; GABA and oxidative stress indicators were divided into three groups according to their control quartiles，respectively ［low level group ( Q1: ＜P25) ，medium level group ( Q2: P25 －P75) ，high level group ( Q3: ＞P75) ］，and conditional logistic regression was applied to analyze the relationship between GABA，oxidative stress indicators and the risk of develo- ping T2DM; the dose-response relationship between GABA，oxidative stress indicators and the risk of developing T2DM was analyzed by using restricted cubic spline ( RCS) ． Results : T2DM group ( P＜0. 05) ．Spearman's correlation analysis showed that GABA level was positively correlated with SOD and GSH-Px activities and negatively correlated with MDA level ( P＜0. 001) ．Conditional logistic regression analysis showed that medium levels of SOD and GSH-Px as well as medium and high levels of GABA were protective factors for T2DM compared with low levels in each group ( P＜0. 05) ．RCS results showed that a negative dose-response relationship between GABA，GSH-Px and the risk of developing T2DM，and SOD showed a trend of decreasing and then increasing the risk of developing T2DM ( P＜0. 05) ． Conclusion Serum GABA levels have been associated with the risk of developing T2DM．As serum GABA levels increase，the risk of developing T2DM may decrease．