Objective: To study the chemical constitutes of Smilax china and the cytotoxic activities of isolated compounds. Method: Various chromatographic techniques were used to separate and purify the constituents.Their structures were established on the basis of their physico-chemical properties and spectral data.The isolated compounds were evaluated for their cytotoxic activities by MTT method. Result: Six steroidal saponins were isolated from the dried rhizomes of S.china. Their structures were established on the basis of spectroscopic evidence (NMR

MS) as borassoside B (1)

dioscin(2)

protodioscin (3)

22-O-methyl protodioscin(4)

isonarthogenin 3-O-α-L-rhamnopyranosyl (1-2)-O- -β-D-glucopyranoside (5)

diosgenin-3-O- -β-D-glucopyranoside(6).Compounds 2 and 6 showed significant cytotoxic activities against K-562 carcinoma cell line at the concentration of 5 mg ·L-1.The inhibitory percentage of compounds 2 and 6 on K-562 cell growth were 89.1% and 90.1% at concentration of 5 mg ·L-1. Conclusion: Compounds 1 and 6 were isolated from this plant and Smilax for the first time.Compounds 2 and 6 showed cytotoxic activities against K-562 carcinoma cell line in vitro.