Abstract: Results from analysing the contents of mono-and oligo-saccharides(total 14 compounds) in different parts of birch(Betula pendula Roth)in spring by gas-chromatography indicated that the major sugars in birch sap were mono-saccharides in which fructose content was about 9．04mg／ml and gluctose content about 4．80mg／ml(measured on April 4),and there were also some trace of disaccharlde and trisaccharide observed．The major sugars in branch and in root were also mono-saccharides． Its contents in branches fluctuated from 15．96 to 13．10 mg/g,in roots from 24．42 to 3．09mg／g(from March 27 to May 18)．Then it is important to collect birch sap according to its physiological changes with time．