The changes in microstructural parameters in varieties of acid dye processed ( Bombyx mori and Antheraea) silk fibers have been studied using wide angle X-ray scattering (WAXS) method. The crystal imperfection parameters like crystal size 〈 N〉, lattice strain ( g) and enthalpy ( α*) have been determined by profile analysis using Fourier method of Warren. These results were crosschecked with the one obtained by matching the simulated intensity profile obtained from one-dimensional Hosemann's paracrystalline model. In all this computation, we have used (201) reflection observed in these silk fibers. We have also computed volume-weighted and surface-weighted crystal sizes and compared the changes in these parameters with the measured physical properties like tensile strength and percentage of elongation at break in these fibers.