Abstract: Folin-Ciocalteu method and sodium nitrite-aluminum chloride method were used to determine total phenolic content and flavonoid content of bound phenolics from the inflorescences, peduncles and leaves of Ottelia acuminata (O. acuminata), respectively. The composition of bound phenolics was analyzed by high performance liquid chromatography (HPLC). The antioxidant activity and protective effect against ROO· mediated DNA damage were also investigated. The results showed that total phenolic content of O. acuminata was in the range of 209.72~366.35 mg GAE/g Extract while total flavonoid content was in the range of 156.69~466.08 mg CAE/g Extract. Five phenolics, namely, caffeic acid, quercetin-3-O-glucoside, luteolin, chlorogenic acid and ferulic acid were identified in bound phenolics of O. acuminata. Trolox equivalent antioxidant activity (TEAC), 1,1-diphenyl-2-trinitrophenylhydrazine (DPPH) radical scavenging ability, iron ion reduction antioxidant ability (FRAP) and hydroxyl radical (·OH) scavenging rate IC₅₀ value of different plant parts were in the range of 1.19~1.25 μmol TE/g Extract, 0.74~0.94 mmol/g Extract, 3.61~4.75 mmol Fe²⁺/g Extract, 0.34~1.26 mg/mL, respectively, among which the leaves displayed the strongest antioxidant activity. In the concentration range of 12.5~500 mg/mL, the percentage of double helix DNA in bound phenolics of inflorescences, peduncles and leaves ranged from 22.74% to 50.07%, 18.25% to 53.28% and 25.93% to 53.60%, respectively, among which the leaves showed the strongest DNA damage protective effect, followed by the peduncles. The results showed that O. acuminata was rich in bound phenolics which possessed strong antioxidant activity and DNA damage protective effect.