Method for measuring concentricity deviation azimuth of optical fiber preform core

The invention relates to a method for measuring the concentricity deviation azimuth of an optical fiber preform core, which comprises the steps that: an optical fiber preform is immersed in matching oil having the refractive index identical or similar to that of the cladding of the optical fiber preform and is then subject to parallel slow motion scanning by laser beams in parallel motion, light-penetrating signals are synchronously acquired and recorded; the center of the cladding is determined through the variation of transmitted light intensity, the coordinate values of the center of the cladding on a projective plane of vertical laser in the incident direction are determined by means of incidence stepping-transmission change method; the coordinate values of the centers of the claddings corresponding to circumferentially-different azimuths are determined by rotating by an angle along the rotating direction and repeating the process; and actual deviation azimuth and deviation value of the cross-section clad