The interaction of femtosecond optical pulses with high order nonlinear effect in fiber communication is re-searched. The numerical results show that the self-frequency shift and self-steepening make the pulse drift backward nonlinearly, and the drift of the former pulse smaller than that of the latter. The latter pulse becomes steep, itswidth is compressed, its peak power is increased, and the former pulse is reversed. When the self-frequency shift and self-steepening effect are considered at the same time, the high order nonlinear effect affects it seriously. The interaction of three and four pulses is similar to that of two pulses.