Nonresonant third-order nonlinear optical properties of amorphousAs2Se3 films were investigated experimentally by the method offemtosecond optical heterodyne detection of the optical Kerr effect at 805 nmwith 80 fs ultrafast pulses. The results have shown that the values of realand imaginary components of third-order susceptibility of amorphousAs2Se3 films were 5.6×10-12 esu and -2.0×10-13 esu, respectively. Amorphous As2Se3 films demonstrateda very fast response time within 200 fs. The ultrafast response and largethird-order nonlinearity are attributed to the ultrafast distortion of theelectron cloud of As2Se3 films.