With maleic anhydride, acrylic and sodium hypophosphite as reactants, a new type of functional agent was synthesized. The effects of concentration of the inishing agent, baking temperature,pH values and concentration of catalyst in the finishing bath were researched. The optimum technological conditions were defined: the finishing agent concentration 8%, baking temperature 190℃, pH 3.5 and sodium hypophosphite concentration 5%, and the fire proof performance of the treated cotton fabric was also tested. After finished, the value of WRA is 252°and LOI is 27.1.