Abstract: A series of stable miniemulsion were prepared from the copolymerization of homemade polyurethane, vinylcontaining silane and acrylate. The influences of the polymerization conditions and content of organosilicone on the properties of copolymer miniemulsion and the membrane were investigated. The result shows that structural well defined polymer made from seed miniemulsion polymerization is obtained, the average particle size and polydisperse index of miniemulsion is about 150 nm and 0.07, respectively, and the water and heat resistance of miniemulsion membrane are improved obviously because of the introduction of organosilicone.