Randomly varying birefringence in optical fiber can lead to pulse broadening, corresponding to polarization-mode dispersion (PMD) effect. Here the interaction between random birefringence and Kerr effect is investigated numerically about dispersion-managed (DM) soli-ton. In zero-averaged-path dispersion managed optical fiber links, because linear dispersion is full compensated, the Kerr effect becomes a detrimental factor in the transmitting system of DM soltion and makes optical pulse narrower. However, when random birefringence is considered, Kerr effect appropriately resists pulse broadening induced by PMD. Systems performance can be improved greatly, as long as PMD is compensated by the nonlinear effect through suitable birefringence parameter and systems power. In addition, considering polarization-dependent losses (PDL), the results show that the fluctuation and broadening of pulse width arc very large even with little loss difference in two polarization directions. So, PDL must be considered in high-bit-rate optical fiber communication systems.