Abstract: The optical soliton nonlinear Schrodinger (NLS) equations with three-order dispersion effect and without three-order dispersion effect were respectively resolved with the split-step Fourier transform method (SSFM). It is found by the numerical solution that the three-order dispersion effect may cause the soliton pair pulse to oscillate on a single side and may produce the sub pulse in the oscillating side; and also found that the phase difference and amplitude proportion play an important role when there is no effect of three-order dispersion, but only phase difference results in the obvious influence on the propagation of soliton pair while there is the three-order dispersion effect, and it can make energy transfer. The effect of amplitude proportion and the phase difference between two soliton pulses on the propagation of soliton pair is discussed.