Objective To investigate the effects of scutellarin and its derivatives on breast cancer cells and the synergistic anti-tumor effects of scutellarin and its derivatives combined with arsenic trioxide. Methods Human breast cancer MDA-MB-23 cells were cultured in vitro and divided into control and test groups. Every group was set 6 wells. Test groups were treated with scutellarin and its derivatives alone and combined with 5μM arsenic trioxide. One of the derivatives of scutellarin is scutellarein， which is the glycone of scutellarin. Scutellarein is also the main metabolism product of scutellarin in vivo. The other derivatives of scutellarin is tetraacetyl scutellarein， which we synthesized to improve the low bioavailability of scutellarin. Inhibition of MDA-MB-23 cells proliferation was tested by MTS assays. Results Scutellarin alone inhibited cell proliferation in a dose-dependent manner， when scutellarein and tetraacetylscutellarein showed slight inhibition effect. It indicated that the glucuronic acid moiety of scutellarin played an important part in cell proliferation inhibition. Both scutellarin and scutellarein combined with arsenic trioxide exerted synergistic effects on proliferation inhibition in MDA-MB-231 cells in dose-dependent manners. Particularly， scutellarein did not inhibit cell proliferation alone but significantly enhance the proliferation inhibition of arsenic trioxide on MDA-MB-231 cells. Conclusion The combination of scutellarein and arsenic trioxide inhibits breast cancer development more effectively than each drug alone.