Abstract: Different fermentation processes will result in different content of γ-aminobutyric acid in tea samples. A method for the determination of γ-aminobutyric acid in Oolong Tea using an automatic amino acid analyzer has been developed, and the trend for the content variation of γ-aminobutyric acid in Oolong Tea using different fermentation processes was investigated. Oolong Tea was soaked for some time, and then determined on a automatic amino acid analyzer. The detection limit of the method was 0.01 g/100g, and the recoveries ranged from 94.4%~109.4%, which meet the requirements of determination. The method with a fast pretreatment procedure has a high throughput and is suitable for the quantitative and qualitative analysis of γ-aminobutyric acid in Oolong Tea, and can be used to investigate different fermentation processes. The determination method is accurate and reliable, which meets the requirements of daily inspection. It also has great significance for the evaluation of the fermentation process whether it can produce high content of γ-aminobutyric acid.