The determination and adjustment of the polarization axis azimuth of the polarization maintaining (PM) optical fiber is of great significance for improving the performance of the optical fiber devices. In order to further improve the accuracy of the aligning axis, the domestic researchers have put forward the fivepoint method and the fivefinger method on the basis of the POL method, and the theoretical alignment accuracy has been improved. However, such methods are limited in practicability because they are based on the premise of specific light intensity distribution and the imaging plane adjustment requirements are high. Based on the sideview imaging of polarizationmaintaining fiber, a large amount of simulation and analysis of the sideview imaging intensity distribution of different imaging planes of polarizationmaintaining fiber have been carried out in this paper. It is found that when the fiber rotates to the vicinity of the slow axis at an angle of 0° to the horizontal direction, the light intensity distribution changes significantly. This phenomenon can be used to identify the 0°position. Therefore, this paper changes the previous idea of aligning the axis by finding a specific light intensity distribution axis, and proposes an alignment method to identify the 0° position. The method can determine the deflection of the polarization axis by simple image processing and data analysis. The applicable imaging plane position range is relatively wider, the operability is strong and the practical prospect is good.