The invention relates to the field of preparation of 
textile auxiliaries. The invention relates to a method for preparing a fluorosilicone waterproof finishing agent for cotton fabrics. The invention provides a waterproof finishing agent specially for cotton fabrics. The finishing agent consists of a medium-length  It is composed of chain 
alkyl cationic polysiloxane 
emulsion and a new type of organic fluorosilicon 
emulsion. During the synthesis process, modified 
silicone oil with higher 
silicon-
hydrogen bond content is added to prevent the 
emulsion from forming a double-layer 
silicone resin film on the polar surface.  The problem of decreased hydrophobicity and water-washing resistance; a new type of organic fluorosilicon 
copolymer emulsion provided by the present invention is obtained by catalytic 
polymerization of short 
fluorocarbon chain monomers and cyclosiloxanes that are low in cost, difficult to degrade, and more 
environmentally friendly.  The problem of high cost and heavy 
pollution of the 
fluorine-containing emulsion is solved; the 
surface layer of the cotton fabric finished by the finishing agent of the invention is smooth and smooth, and the 
hydrophobic effect is better.  Combined with softness and hydrophobicity, it is a product with great potential, profound meaning and great production value.