After the fiber itself absorbs water, it will produce a certain degree of swelling. Usually, the swelling of fibers is anisotropic (except nylon), that is to say, shorter length and larger diameter. The percentage of the length difference between the fabric and its length before and after water is usually called shrinkage. The stronger the water absorption, the stronger the swelling, the higher the shrinkage and the worse the dimensional stability of the fabric.

After water, the fabric length is further shortened because of the swelling of the fiber itself, resulting in shrinkage. The shrinkage of fabric is different with different weaving rate. The fabric itself has different fabric structure and weaving tension, and its shrinkage rate is different. When the weaving tension is large, the fabric is loose and thin, and the fabric shrinkage is small, and the shrinkage rate of the fabric is high. The fabric is compact and thick, and the shrinkage rate of the fabric is large. The shrinkage rate of the fabric is large when the weaving tension is large, and the fabric is loose and light, and the shrinkage rate of the fabric is small. In the process of dyeing and finishing, in order to reduce the shrinkage rate of the fabric, the weft density is increased and the shrinkage rate of the fabric is increased in advance by the way of pre-shrinkage finishing, so as to reduce the shrinkage rate of the fabric.