Abstract:In order to reveal the characteristics of free amino acids (FAAs) profile in fresh leaves of oolong tea cultivars, young and mature shoots harvested from oolong tea cultivars in spring and autumn were detected by high performance liquid chromatography and classified by statistical pattern recognition, the young shoots (two or three leaves and a bud) and mature shoots (two to four leaves and a banjhi bud) of green tea cultivars in spring were used as controls. The results showed that all tea samples could be divided into two groups, oolong tea cultivars and green tea cultivars. The effect of shoots maturity on the FAAs profile in fresh leaves of oolong tea cultivars was second only to the difference of tea sample groups caused by tea tree variety characteristics. Furthermore, the objective group differences could be verified among young shoots (green tea cultivars vs oolong tea cultivars) in spring, mature shoots of (green tea cultivars vs oolong tea cultivars) in spring, (young shoots vs mature shoots) of oolong tea cultivars in spring, (young shoots vs mature shoots) of oolong tea cultivars in autumn, young shoots of oolong tea cultivars (spring vs autumn), and mature shoots of oolong tea cultivars (spring vs autumn). The different sources of fresh leaves (cultivars, shoots maturity and harvesting season) had significant or extremely significant effect on the total amount of FAAs and most of the components of FAAs. The higher contents of glycine, leucine and lysine and the lower content of γ-aminobutyric acid were the main difference components of fresh leaves in spring between oolong tea and green tea cultivars. The young shoots of oolong tea cultivars had higher content of arginine than mature shoots in the same harvesting season, and there were different characteristic components of fresh oolong tea leaves with different shoot maturity in spring and autumn. Therefore, it was suggested that the genetic characteristics of tea cultivars were dominant factors affecting the FAAs profile in fresh leaves. The specific chemical pattern of FAAs in fresh leaves of oolong tea provided a necessary material basis for the quality formation.