Abstract: Isopimaric chloride(compound 2) was synthesized by using isopimaric acid as raw material. Then four new isopimaric thiophene sulfonamides derivatives:isopimaric acid acyl-4-bromo-2, 5-dichlorothiophene-3-sulfonamide(5a), isopimaric acid acyl-5-bromothiophene-2-sulfonamide(5b), isopimaric acid acyl-5-chloro-4-nitro-sulfonamide (5c), and isopimaric acid acyl-thiophene-2-sulfonamide(5d) were prepared by aminolysis reaction from compound 2 and thiophere sulfonamides which were connected with p-phenylenediamine. The structures of the compound were confirmed by FT-IR, ¹H NMR, ¹³C NMR, and ESI-MS. In addition, the cell proliferation inhibition assay (MTT method) was used to study the in vitro inhibitory activity of 5a-5d on four human tumor cells. The results showed that compound 5b had inhibition rates of 91.36%, 94.06% and 92.26% against Hela, MDA-MB-231 and Hep G-2 at the concentration of 100 μmol/L, besides, the inhibition rate against PC-3 was 86.93%, which was close to 90%, indicating that compound 5b had good antitumor activity. Through the determination of IC₅₀ value, it was further concluded that the inhibition effect of compound 5b was better than that of 5-fluorouracil (5-FU), a widely used anticancer agent in clinic.