Abstract: Free-standing graphene films (GFs) as functional materials require high mechanical performance for a convenient industrial processing.GFs were prepared from graphene oxide films by annealing temperatures from 1 300 to 1 700℃,and were characterized by AFM,XRD,SEM,Raman spectroscopy and mechanical testing.Results indicate that the samples have a maximum tensile strength and fracture strain of 22.41 MPa and 2.44%,respectively and a minimum thermal conductivity of 744 Wm^-1·K^-1 for an annealing temperature at 1 500℃.This is related to physical interlocking which results,from surface wrinkles of the graphene layers.