Small-angle X-ray scattering (SAXS) was used to evaluate various macromolecular parameters of Nylon 6 textile fiber at denier values of 15/1, 18/1, and 20/1 treated at different temperatures within the range of 20-63 degrees C. The theories of Kratky, Pored, Bueche, and Wendorff were applied to the densely packed two-phase system of Nylon 6, which conforms to the general micelle system. The values determined for the parameters, such as microvoid dimensions (d), the void percentage (w(1)), the length of coherence (lc), the specific inner surface (o/v), and the transversal lengths (l(1) and l(2)) of Nylon 6 fiber at a denier value of (15/1) at temperature 38 degrees C are 62.5 Angstrom, 0.0181%, 480.55 Angstrom, 3.214 x 10(-6) Angstrom(-1), and 225 Angstrom and 1244 x 10(3) Angstrom, respectively. A comparative study of the above parameters at different temperatures was also made and a correlation was established.