To study the chemical constituents in leaves of Tripterygium wilfordii Hook F, and to explore the proapoptotic action of burselignan on SMMC-7721 cells and its molecular mechanism. Various chromatographic approaches were employed for separating chemical constituents, and compounds were structurally elucidated based on physicochemical properties and spectral data. Antiproliferative activity of burselignan on SMMC-7721 cells was detected by MTT assay, and burselignan's effects on Bcl-2, Bax and Survivin protein expressions were analyzed by Western blotting. Five compounds were isolated and identified, namely lyoniresinol, isolariciresinol, burselignan, dibutyl phthalate and daucosterol. Burselignan inhibited the proliferation of SMMC-7721 cells. Western blotting showed that burselignan could increase Bax expression, and decrease Bcl-2 and Survivin expression. Burselignan can significantly inhibit the proliferation of SMMC-7721 cells, and induce their apoptosis by regulating the expression of Bax, Bcl-2 and Survivin proteins.