Cotton fabric was treated with various concentration of sulfuric acid solution at 3$pm$1$^{circ}C$. The iodine adsorption value(ISV) in I2-Kl solution was determined by titration method. The crease recovery angle, breaking strength and elongation of the treated fabrics were measured. The crystallinity measured by the ISV was compared with that measured by x-ray diffraction. The ISV of treated fabrics increased with the increase of sulfuric acid concentration up to 10% but above that concentration the tendency diminished. At 65% of sulfuric acid solution, the ISV decreased rapidly due to the degradation of cellulose molecules. Some physical properties of treated labrics changed with the ISV. The tendency of variation of crystallinity measured by the ISV was agreed with that measured by x-ray difration pattern.