Graphene has attracted a great deal of interest due to its fascinating properties and a wide variety of potential applications. Several methods have been used to achieve high-quality graphene films on different substrates. However, there have been only a few studies on graphene growth on iron (Fe) and the growth mechanism remains unclear. This paper systematically investigates temperature-dependent growth of graphene on Fe substrate by gas-source molecular beam epitaxy. Two-dimensional (2D), large-area graphene samples were grown on Fe thin films, and characterized by Raman, X-ray photoelectron spectroscopy, X-ray diffraction, optical microscopy, transmission electron microscopy and atomic force microscopy. It is found that graphene flakes can be grown on Fe at a growth temperature as low as 400 degrees C and the optimized large-area graphene growth temperature is relatively low between 500 degrees C and 550 degrees C . The graphene growth on Fe that undergoes the formation and decomposition of iron carbide is discussed. (C) 2017 Elsevier B.V. All rights reserved.