Abstract: A method for determination alanine, serine, glutamic acid, asparagine, theanine, glutamine in tea leaves by MSTFA derivatization has been established. And six amino acids were detected successfully. Isotope abundance of alanine, serine, glutamate, asparagine, theamine and glutamine are calculated accuracy, isotope abundance range from 10% to 98% (atom%). The relative standard deviations (RSD, n=3) were below 0.6%, and absolute deviation were below 0.6%. The method is quick, easy and accurate, which can meet the detection on isotope abundance of labeling amino acids in tea leaves. Besides, the method also can be applied to the determination of isotopic abundance of amino acids in other different crops, and provides technical support for the research of amino acids related transformation pathways and metabolic cycles in plants.