Recently, a noncontact technique based on the temperature dependent Raman band shift has been applied for thermophysical characterization of low dimensional nanomaterials. However, the difficulty of accurately determining the laser absorption significantly limits the accuracy of this Raman technique. This paper presents a transient "laser flash Raman spectroscopy" method to characterize the thermal diffusivity, thermal conductivity and thermal contact resistance of 2D nanomaterials and the laser absorption can be easily eliminated by a normalization technique. The thermophysical properties can be determined by fitting the curves of the normalized temperature rise versus the laser heating time for various laser spot radii. Moreover, if the thermal contact resistance is neglected, the data analysis process is much more convenient and the relative error caused by neglecting the thermal contact resistance is only 1%. (C) 2014 Elsevier B.V. All rights reserved.