The present study aims to synthesize gold nanoparticles (GNPs) by green method using Pterocarpus marsupium and to study the effect of various parameters like stirring, pH, and temperature on morphology and stability of GNPs. The study was further extended to evaluate the role of antioxidants in the green synthesis of GNPs. Formation of GNPs was confirmed by visual color change from colorless to wine red and UV-Visible spectrophotometry. Particle size was found to be in the range of 72-85nm. There was no significant difference in the size and shape of GNPs prepared by different conditions; however, difference in zeta potential suggested difference in stability. GNPs prepared by heating (40 degrees C) were comparatively more stable than GNPs synthesized at different conditions. Fourier-transform infrared spectroscopy suggests the presence of flavonoids and polyphenols. X-ray diffraction studies revealed the crystalline nature of GNPs, while transmission electron microscopy studies suggested mixed morphology of GNPs. In vitro stability studies revealed that GNPs were stable in all conditions except at lower pH and 5% NaCl solution. Synthesized GNPs were found biocompatible in nature. This ecofriendly method for the synthesis of GNPs is rapid and easy which yields stable and biocompatible GNPs which could be used for many biomedical applications.