Green synthesis of nanoparticles which have eco-friendly favourable solvent systems and environmentally reducing agents is of excessive importance. In this paper, we aimed to develop environmentally friendly, rapid and simple producer for the synthesis gold nanoparticles (Au-NPs) using aqueous extract of sumac as reducing agents for gold ions as well capping agent for the bioformed Au-NPs. The bio-synthesized Au-NPs were characterized by the UV-visible spectroscopy, FTIR, TEM, and zeta-potential measurements. The surface plasmon resonance band centred at 520 nm for Au-NPs was characterized by UV-visible spectrophotometer. The probable bio-molecules are polyphenols may responsible for reduction of gold ions were recognized through FT-IR. The TEM result shows the bioformed Au-NPs are spherical in shapes with the mean size of 20.83 ±4.4 nm. The capping of anionic bio-molecules on the surface of Au-NPs was confirmed by zeta potential assessment (-25.3 mV) and is responsible for the electrostatic stability. In vitro antioxidant activity studies showed that DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2, 2'-azino-bis 3-ethylbenzthiazoline-6-sulfonic acid) activities increased in a dose dependent manner. The bio-synthesized nanoparticles can potentially useful in pharmaceutical and biomedical applications.