Abstract: Foam technology is applied to the process of water and oil repellent for polyester/cotton and one side of the finished fabric gets water and oil repellent with inner side still breathable. The paper studied the influencing factors in the process of foam technology, got the optimal parameters through orthogonal test, and it is that Sodium dodecyl sulfate 3g / L, Stabilizer 2g / L, Repellant SMS 60 g / L, Speed 7m/min, Foaming ratio 11.4, Curing conditions 140℃×5min. Meanwhile，comparing the traditional pad-cure-bake method with the new foam technology, it is found that the two methods get equal effect, but the mechanical property of the finished fabric using foam technology is better than that of finished fabric by traditional method.

Key words: polyester cotton, foam, water and oil repellency, single side