Abstract: A nano-alumina/organic fluorine composite emulsion was prepared via in-situ polymerization using organic monomer and self-synthesized nano-alumina as raw materials. The nano-alumina was modified firstly by coupling agent to endow active groups onto the nano-particle surface. The structure and morphology of the modified and unmodified nano-alumina and the as-synthesized composite emulsion were characterized by different methods. The waterproof and oil-repellency properties of the composite emulsion were tested through treating the polyester fabric. The results show that the nano-alumina modified by coupling agent KH-570 could be perfectly dispersed in the organic monomer emulsion and the composite emulsion synthesized through in-situ polymerization. The waterproof and oil-repellency properties of the as-synthesized composition emulsion using coral nano-alumina as the raw material were proved to be stronger than using the sphere nano-alumina as the raw material. Moreover，the as-synthesized composite emulsion using coral nano-alumina as the raw material has many advantages such as small dosage，low baking temperature and permanent function compared with the conventional organic fluorine emulsions.