The nonlinear generalized Schr?dinger equation is applied to describe the propagation of femtosecond laser pulses and supercontinuum generation in a microstructured optical fiber, and solved by using the split-step Fourier method. And the role of self-steepening, intra-pulse stimulated Raman scattering(SRS) and third-order dispersion are discussed adequately. The numerical results show that solition self-frequency shift is generated in a microstructured optical fiber. It is also found that intrapulse stimulated Raman scattering and self-phase modulation result in spectral broadening based on the fission of higher order solitions, and two lagging solitions occur in the time domain. The third-order dispersion and self-steepening influence on the shape of spectrum little, having the opposite effects with SRS. Self-steepening has relatively bigger influence on the ultra-short laser pulse than the third-order dispersion.