Abstract: OBJECTIVE To study the volatile constituents of traditional Chinese medicine (TCM) Oroxyli Semen's antitumor effect, and the basis to give the chemical analysis of it. METHODS Used in vitro method to carry out the effect on inhibition experiment of human liver cancer SMMC-7721 cells. For the anti liver tumor effective constituents in Oroxyli Semen by GC-MS analysis method, to carry out the chemical analysis study. RESULTS Oroxyli Semen volatile constituents had obvious inhibitory effect in human liver cancer SMMC-7721 cells. The volatile constituents were analysis by GC-MS method, deduced the 19 kinds of compounds, sterols, ketone compounds to the highest levels. CONCLUSION Oroxyli Semen volatile constituent is effective constituents, and it play to the role of antitumor, its efficacy constituents for hydrocarbons, benzene, sterol, acids, esters, ketones and other compounds.