Three new monoterpenoid coumarins, zantholin A (3), altissimacoumarin P-Q (5, 6), two new monoterpenoid phenylpropanoids, altissmaphenylpropanoids A-B (2, 4), along with two known compounds (7, 8), were obtained from aqueous EtOH extracts of the root bark of Ailanthus altissima. The assignments of their structures were conducted via extensive analyses of the spectroscopic data. The evidence for the reassignment of the relative configuration in compound 1 was obtained from acetonide analysis, which was also used for assigning the relative configuration of compounds 2 and 6. The utility of statistical procedure (DP4+) was assessed for the relative stereochemistry of compounds 3 and 4. The relative configuration of compound 5 was verified utilizing NOE differential spectroscopy and computational methods. A combination of Mosher's method, optical rotation calculations and a plausible biosynthetic pathway was used to confirm the absolute configuration of compounds 1–6. Moreover, the compounds were tested for their anti-tumor effects against two hepatoma carcinoma cell lines (HepG2 and Hep3B).