Effects of the periodically inhomogeneous birefringence on the dispersion-managed soliton propagation are investigated by the numerical simulation. It is found that the birefringence leads to the disintegration of the soliton, enhances the interaction between solitons, and there is the worst period length corresponding to the largest effect. The theoretical analyses prove the existence of the worst period length by the variational approach, and the worst period length relates to the dispersion map and the pulse amplitude. Finally the nonlinear gain combining the filter is introduced to suppress effectively the effects.