The invention relates to a helicase which is a compound enzyme extracted from a snail crop or a snail digestive tract, the helicase mainly contains twenty kinds of enzyme including cellulose, pectinase, amylase, prolease and the like and is a byproduct in comprehensive utilization and development of snails, however, in the practical processing, the internal organs of the snail are always discarded, so that great waste of enzyme resources is caused. The helicase is a good compound enzyme system containing the pectinase, the amylase and the cellulose; the helicase which is a natural compound enzyme system is applied to a biological refining process of a cotton woven fabric to remove pectin, waxiness and other impurities in cotton fiber under the hydrolytic action of the helicase, therefore, the purposes of improving the wettability and the whiteness of the cotton fabric are achieved. The helicase is adopted for refining the cotton fabric, the helicase has the environment-protecting and energy-saving characteristics, the snail processing byproducts can be comprehensively utilized, the requirement for the current sustainable development is met, and the comprehensive development of the dyeing and finishing industry and the processing industry for snail agriculture products are facilitated.