Aims: The plant Gyrocarpus asiaticus Willd mainly found in south India comes under the family Hernandiaceae. Present phytochemical analysis by GC-MS is to identify compounds and their structural determination and examine antioxidant properties of the plant. Methodology: GC-MS analysis of a hydroalcoholic extract of Gyrocarpus asiaticus Willd was done on Shimadzu QP 2010 Ultra, and carrier gas was used as Helium and Nitrogen. In-vitro antioxidant activity of hydroalcoholic extract carried out by 2, 2-diphenyl-1-picrylhydrazyl (DPPH) method, Ascorbic acid used as a standard drug and analyzed by UV-Visible spectrophotometer (Analytical 2008). Result: The GC-MS analysis of the hydroalcoholic extract shows there are several phytochemical constituents present. From the library of the GC-MS, there are a total of 105 compounds are identified like Alpha -toluenephosphoric acid, 1,2-Benzenedicarboxylic acid, diethyl ester, n-Tetradecanoic acid, Eicosen-1-ol, N -Tridecoic acid, Phytyl eicosanoate, Pentadecane carboxylic acid, Heptadecanoic acid, 9-Octadecenoic acid, Octadecanoic acid, Doxepin, Rotenone, Vitamin D3, Vitamin D2, Beta carotene, Calcifediol, Vitamin E, Amoxapine, Cholesteone. The in-vitro antioxidant study of 20,40,60,80,100 μg/ml concentration of the hydroalcoholic extract of the plant shows % of free radical scavenging activity like 46.07, 56.27, 68.35, 73.89, and 73.55 and shows IC50 value 44.63. Conclusion: The hydroalcoholic extract of Gyrocarpus asiaticus WILLD shows various biologically active compounds and significant antioxidant activity.