In order to investigate the influence of fiber birefringence on the pol arization maintaining ability of fiber coil for gyroscope,three different types of optica l fiber are selected and the same winding method is used to fabricate the same type fiber co il.The polarization coupling distribution of the fiber coil is measured by white light interferometer, and the birefringence of the coiled fiber is calculated by identifying coupling interference peak caused by the fusion point of the pigtail at both ends of the fiber coil an d the white light interferometer.The influence of birefringence on the polarization maintaining a bility of fiber is analyzed by comparing the test results of different fiber coils.The measurem ent results show that the birefringence of the three kinds of fiber coils are 7.47×10－ 4,6.36×10－4 and 5.78×10－4 respectively,and the whole polarization coupling amplitudes of the three fiber coils are －74.79dB,－70.06dB and －64.97dB respectively.Five large coupling points at the same position are selected for statistic polarization coupling amplitude induced by e xternal stress, and the average polarization coupling amplitude is －57.85dB,－49.85dB and －44.49dB,respectively.The experimental results show that the high birefringence f iber can improve the whole plarization maintaining ability of the fiber coil,and the high birefring ence fiber has a strong ability to resist the influence of external stress.