Experiments on the correlation analysis of backward diffractive patterns in different azimuths to determine the polarization axes of PANDA fiber were made in order to solve the problem to built a standard library of diffractive patterns.The experiments show that there are three characteristics of the patterns:the diffraction patterns in the fast axis direction is different from that in the slow axis direction; the diffraction patterns near the fast or slow axis are similar,and the diffraction patterns in the fast axis or the slow axis direction are symmetric.Based on the three mentioned characteristics,a new method without standard library of diffractive pattern was put forward to determine the special azimuths of polarization axes of PANDA fiber with image cross correlation.It is not necessary to build a standard library for the diffractive images to determine the special azimuths of polarization axes of PANDA fiber.