Abstract: Holographic interferometric data are interpreted in detail, and Abel inversion of measurements of optical path length through refracting cylindrical symmetric plasmas is discussed and numerically studied. By expanding refractive index of plasma as truncated Fourier Bessel series and determining the expanded coefficients in the least-mean-square sense, Abel inversion is realized. Numerical results show that, if electron density of plasma is low, i.e., about one tenth of the critical density of probe light, the precision of the method used in the paper is satisfying, even if the object plane of image system deviates a little from the symmetrical axial of plasmas.