Abstract: The flavonoids content (AlCl₃-NaNO₂ method) and total polyphenol contents (Folin-Ciocalteu method) of 10 kinds of Guangdong medicinal and edible plant extracts were determinated. The antioxidant activity (DPPH radical scavenging activity and hydroxyl radical scavenging activity) and the antiproliferation activity of mice colorectal cancer MC-38 cell (CCK-8 kit method) were evaluated. The correlation between the activity of active substance and its contents were analyzed. The results showed that the highest content of total flavonoids was galangal (85.76 ± 3.25 μmol CE/g DW) of 10 Guangdong medicinal and edible plants, and the lowest content of total flavonoids were Kaempferia (0.80 ± 0.05 μmol CE/g DW) and longan (0.69 ± 0.03 μmol CE/g DW). The highest content of total polyphenol (226.26 ± 9.17 μmol GAE/g DW), and the lowest content of total polyphenol was Kaempferia (7.52 ± 0.67 μmol GAE/g DW). The DPPH free radical scavenging activity of the strongest for galangal, the weakest activity for Kaempferia. The activity of scavenging hydroxyl free radical was strongest in Kaempferia, Alpinia oxyphylla and nutmeg(there was no significant difference among them), and the activity was weakest in orange peel. The anti-MC-38 cell proliferation activity was strongest in orange peel and galangal, and weakest in longan. DPPH radical scavenging activity was significantly correlated with the content of total flavonoids and total polyphenols (P<0.05). The correlation between Anti-MC-38 cell proliferation activity and the content of total flavonoids and total polyphenol was very significant (P<0.01). There was no significant correlation between the scavenging activity of hydroxyl radical and the content of total flavonoids and total polyphenols. Although the active efficacy of water extract of edible and medicinal plants had dose effect, it was also affected by the kinds and synergistic effects of its components.