The split-step Fourier method is used to simulate the impact of ultra-short pulse with third-order nonlinear dispersion.In the frequency of Drude model of selecting certain range,the impact of third-order nonlinear dispersion to ultra-short pulse can not be ignored by numerical calculating.When third-order nonlinear dispersion is negative,the results show that in the normal dispersion,ultra-short pulse is wide asymmetric and pulse central drifts to the forefront; in zero dispersion,the degree of asymmetry broadening of ultra-short pulse increass and the center of pulse which drifts to the forefront had a oscillation only in the forefront of pulse.In anomalous dispersion,ultra-short pulse is asymmetry narrow,the central of pulse also drifted to the forefront.