A series of paeonol derivatives have been synthesized by simple acylation and etherification of the paeonol. Anti-tumor activities of the synthesized compounds were evaluated against HeLa and MCF-7 cells lines in vitro by the standard MTT assay. It was found that the derivatives were more active against HeLa than MCF-7. The results also indicated that 4-methoxy group is the synergistic group of paeonol's anti-tumor activity and ketone carbonyl side chain is essential functional group of paeonol's anti-tumor activity. Compound 2d had stronger antiproliferative activities than paeonol against HeLa and MCF-7 cell lines with IC50 values of 2.67 and 4.74 micromol x L(-1) respectively. The results showed that paeonol derivatives were worth to be intensively studied further.