Monte Carlo Simulations for time characteristics of ultrashort pulse light propagation in the skin four-striated scattering medium are presented. Variations of diffusive intensity with the radial distance and angle at different time are given. The frequency-domain results of time response of surface diffusive intensity are obtained by using Fourier transformation. The results show that the diffusive intensity changes with time to the extent of magnitude and its time-resolution is in the order of ps, so the detector with large dynamic range and ps time-resolution is needed. The results from the frequency-domain analyses show that the amplitude and phase have significant changes at very high frequency, but the realization of the detection is not feasible.