Chemical constituents in methanol extracts from stem of Tetraena mongolica Maxim. were analyzed by GC-MS technique. The results show that 86 peaks are isolated in methanol extracts from stem of T. mongolica and 50 compounds are identified with accounting for 82. 16% of total contents. Relative content of 8 compounds are over 3%, in which, relative content of 1-(2-methyl-5-vinylcyclopent-1-enyl)-ethanone is the highest (7. 42%). These compounds can be divided into ketones, esters, carboxylic acids, alcohols, steroids, etc. In which, relative contents of ketones and esters are 32. 49% and 27. 55%, respectively, which are the main components in methanol extracts from stem of T. mongolica.