Abstract: Curcumin has been reported to possess antitumor activity with low toxicity. However, the clinical application of curcumin has been significantly limited by its instability and poor metabolic property. In order to overcome these limitations and discover novel small molecules with potential antitumor activity, 29 curcumin mimics were synthesized, which were confirmed by ¹H NMR and HR-MS, and their cytotoxic property was evaluated against five human cancer cell lines in vitro. Compounds 16, 18 and 19 exhibited good cytotoxic property, their IC₅₀ value were even below 5 μmol·L^-1 to some cancer cell lines, 5-9 times better than curcumin.