The ultrafast third-order nonlinear optical properties of graphene in both suspension and film status are studied using femtosecond time resolved optical Kerr gate technique at 800 nm. The third-order nonlinear optical susceptibility is 4.2 x 10(-14) esu for solution of 0.010 mg/ml. The corresponding second-order hyperpolarizability is 3.4 x 10(-32) esu per carbon atom in graphene, which is the largest among the carbon family. The graphene embed in the polymer matrix of polyvinyl alcohol film (OD = 0.43) exhibits strong ultrafast nonlinear optical response of 3.3 x 10(-12) esu and shows its potential application in non-linear optics. (C) 2011 Elsevier B.V. All rights reserved.