In order to improve the dimension stability of the cotton fabric, usually using 180-280 - g/L of caustic soda for mercerizing. Because of its high viscosity of lye, poor permeability and a careless handling will cause the surface of the cotton fabric mercerizing phenomenon, therefore can join mercerizing osmotic agent. It can reduce strong lye table du Tension, promote the penetration of lye, not only make mercerization quickly even, and can greatly shorten the mercerized time. Fatty alcohol phosphate salt is one of the important components of mercerizing osmotic agent, carbon atom number should be less than 8 fatty alcohols, best for 4 to 6, because of the shorter the carbon chain fatty alcohols, fatty alcohol phosphate salt alkali resistance is relatively higher. Fatty alcohol phosphate salt with special performance, it is in neutral aqueous solution of low surface activity, permeability is poor, but in the 180-280 - g/l_ lye ?