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 800nm. The third-order nonlinear optical susceptibility is 4.2×10 −14 esu for solution of 0.010mg/ml. The corresponding second-order hyperpolarizability is 3.4×10 −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 3.3×10 −12 esu and shows its potential application in nonlinear optics.