Agaricus campestris is a traditional Indian medicinal plant that exhibits biological activities, such as anti-diabetic activity, Antipyretic Activity, and Anti-inflammatory Activity. Not with standing little data is accessible regarding its antioxidant activity. The basis of this analysis is to study the antioxidant activity of a bioassay-guided fractionation and its active compounds/components. High-performance thin-layer chromatography (HPTLC) and preparatory high-performance liquid chromatography (pre-HPLC) were used to isolate compounds and to determine their structures through mass spectrometry (MS), nuclear magnetic resonance (1H &13C NMR) and Fourier transform infrared spectroscopy (FT-IR) spectroscopic analyzes. 3 compounds were isolated from fraction among them. Methoxydiazine (AC-1), afrormosin (AC-2), and candidol (AC-3) were reported from Agaricuscampestris. They were showed an excellent antioxidant activity potential at concentrations (100, 200, 300, 400 and 500μg/mL) compared. In conclusion, AEAC may have therapeutic potential for antioxidant effects. AC-1, AC-2, and AC-3 as an effective antioxidant activity.