A new compound 1 (named botryosphaerin F), along with other three known compounds 2 (13,14,15,16-tetranorlabd-7-ene-19,6b:12,17-diolide), 3 (botryosphaerin B) and 4 (LL-Z1271β), has been isolated from the mangrove fungus Aspergillus terreus (No. GX7-3B). The structure of the new compound was established by analysis of spectroscopic data. The hypothetical biogenic relationship of four sesquiterpene analogues was also described in this paper. Furthermore, in the cytotoxicity assays, compound 1 showed potent inhibiting activity towards MCF-7 and HL-60 cancer cell lines with 50% inhibition of cell growth (IC50) values of 4.49 and 3.43 μM, respectively, and compound 4 exhibited promising activity against HL-60 cell line with an IC50 value of 0.6 μM.