Abstract: Objective:Determination of nutrient contents and antioxidant activity in water extracts of Gastrodia elata. Method:Wet Gastrodia elata was collected, dried and smashed after atmospheric cooking, heat reflux extraction, decolorization and the dry powder of Gastrodia elata was obtained by freeze-dried, and then the contents of water, ash, starch, crude protein, crude fat, total polysaccharides, carbohydrates, total polyphenols, total flavonoids, procyanidin and gastrodin of the aqueous extract of Gastrodia elata were measured. The antioxidant activity of aqueous extract of Gastrodia elata was evaluated by four methods. Results:The contents of water, ash, starch, crude protein, crude fat, total polysaccharides, and carbohydrates in Gastrodia elata extraction were 4.60, 1.55, 40.30, 9.21, 4.01, 38.24 and 79.80 g/100 g respectively. And the highest contents of potassium in minerals was 25477.45 mg/kg. The contents of total polyphenols, total flavonoids and procyanidin in the aqueous extract of Gastrodia elata was 17.0 mg/g, 9.0 mg/g, 3.3 mg/g, and the contents of gastrodin and p-hydroxybenzyl alcohol was 2.87% and 0.64%. Seven polyphenols were detected by UPLC, and the highest content of valerin was 161.96 mg/100 g. The aqueous extract of Gastrodia elata had moderate reduction ability and scavenging ability to free radicals, and its reducing power and scavenging ability to free radicals increased in a dose-dependent manner with the increase of extract concentration. When the concentration of the aqueous extract was 0.2, 10, 1 and 0.1 mg/mL, the total reducing power, DPPH·scavenging rate, OH·scavenging rate and O₂^-·scavenging rate reached 1.05, 90%, 76% and 58% respectively. Conclusion:The aqueous extract of Gastrodia elata had broad prospects for development and application due to its nutritional value and high antioxidant potential.