To study the chemical constituents of Euphorbia antiquorum L., the constituents were isolated with normal-phase and reverse-phase silica gel column chromatography and their structures were elucidated on the basis of spectroscopic data. Seven terpenoids were obtained from EtOAc extract of E. antiquoru L. They were identified as antiquorine A (1), antiquorine B (2), ent-13S-hydroxy-16-atisene-3,14-dione (3), taraxerol (4), 3beta-hydroxy-25,26,27-trisnorcycloart-24-oic acid (5), 9beta,19-cyclolanostan-3beta-ol (6) and psi-taraxastane-3,20-diol (7) by spectral analysis. Compounds 1-3 are diterpenoids, which belonged to abietane, ent-kaurane and atisane respectively. Among them, compounds 1 and 2 are new compounds. Compounds 4-7 are triterpenoids, and compound 5 is a degraded cycloartane triterpenoid which is a new natural product. Compound 7 was isolated from this plant for the first time. It demonstrated that the chemical structures of constituents in this plant were diverse.