All-optical fiber current sensor of power cable can accurately detect the characteristic current of cable operation and fault current, which greatly improves the safe and stable operation of power cable. However, due to its structural characteristics, there is a great lack of stability and reliability in the measurement process, which limits all-optical fiber current transmission. Sensors are applied in practice. In this paper, the transmission field of a symmetrical helical nested all-fiber current sensor is simulated by COMSOL. The variation of polarization state of light wave under the action of linear birefringence effect and multi-dimensional deviation of polarizer is simulated and compared. The results show that the position deviation of the polarizer has a significant effect on the polarization measurement results, and the synergistic effect of the multi-dimensional deviation of the polarizer and the linear birefringence on the polarization measurement results is strengthened with the increase of the current.