During this paper, palladium nanoparticles were immobilized on the surface of Fe3O4 using Hibiscus tiliaceus L. extract as a stabilizing and reducing agent. The green synthesized Pd/Fe3O4 nanocomposite was characterized by FT-IR, UV-Vis, TEM, XRD, VSM, FESEM and EDS. The prepared Pd/Fe3O4 nanocomposite was used an efficient catalyst for the reduction of Cr(VI), 4-nitrophenol (4-NP) and 2,4-dinitrophenylhydrazine (2,4-DNPH). The catalytic activities of the Pd/Fe3O4 nanocomposite in reactions were monitored by using UV-Vis spectroscopy. It can be recovered and reused six times without remarkable loss of its catalytic activity.