In this paper,symmetrical slit-step Fourier numerical method is used to simulate the soliton transmission properties in the fibers presenting birefringence.When the polarization angle of incidence is 30 °,the inferences of the group velocity mismatch which denotes the magnitude of the birefringence on the soliton transmission are analyzed.It is shown that the magnitude of birefringence affects the drift extent of pulse peak on the time-axis.The larger the birefringence,the longer the drift will be.If the birefringence of the fiber is randomly varying,the drift of the pulse peak will be corrected.The intensity of the two polarization component of the soliton change irregularly with the transmission distance but the composite intensity of the soliton pulses hardly varies because the two polarization component compensate each other.The randomly varying birefringence enhances the interaction of the soliton,but the non-linear gain can effectively inhibit the interaction of soliton transmission.That makes the adjacent solitons which tend to be overlapping and separating to avoid deviating from the original time slot.It achieves a good control over polarization mode dispersion.