This work was focused on the synthesis and characterization of iron nanoparticle loaded sawdust carbon (Fe/SC) by low cost green synthesis approach and its application for catalytic pyrolysis of heavy oil. Fourier transform infrared (FT-IR), X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS) and inductively coupled plasma optical emission spectrometer (ICP-OES) methods were used to analyze the catalyst of Fe/SC. The properties of heavy oil before and after reaction were characterized by SARA analysis, FT-IR, gas chromatography-mass spectrometry (GCMS) and thermogravimetric analysis (TGA). The experimental results showed that after pyrolytic reaction at 350℃ for 30 min with 0.1 wt% catalyst, the viscosity of heavy oil may decrease by 80.81% with a net efficiency of catalyst of 20.68%. The catalyst of Fe/SC is promising, low cost, high efficiency, highly stable and eco-friendly for catalytic upgrading and viscosity reduction of heavy oil.