Phosphate functionalized graphene oxide (PGO), prepared by covalently bonding triethylphosphite on to the surface of graphene oxide (GO) via Arbuzov reaction has been demonstrated as an efficient catalyst for three component Biginelli condensation reaction with excellent yield (96%) under microwave condition. The PGO nanocatalyst was thoroughly characterized by Fourier transform infrared spectra (FTIR), FT-Raman spectroscopy, Powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Field-emission Scanning electron microscopy (FE-SEM), Energy dispersive X-ray spectroscopy (EDS), N-2 adsorption/desorption study, Ammonia temperature-programmed desorption analysis (NH3-TPD) and Thermogravimetric analysis (TGA). The presence of acidic groups on PGO which play an important role in the catalytic transformation were measured by NH3-TPD analysis. Based on the catalytic results, a feasible catalytic mechanism has been proposed. Besides high catalytic activity, this nanocatalyst showed good recyclability, suggesting its potential applications for the synthesis of other important organic molecules.