Polyether-grafted Polysiloxanes was synthesized by microwave irradiation from methyl hydrogen silicone Polyoxyethylene polyoxypropylene acetate, The optimum reaction conditions were determined as follows: radiation power of 600w, the molar ratio of polyether and silicone of 1.2:1, amount of chloroplatinic acid catalyst 10mg/kg, temperature of 90℃ and 40min microwave irradiation. Under the optimum conditions, the everage conversion ratio was 94.7%. The structure of sample was analyzed and characterized by method of FTIR and 1H-NMR. Polyether-grafted Polysiloxanes was used to produce antifoaming agent and applied in metal cleanser. The results showed that the antifoaming agent demonstrate superior antifoaming performance and washing effect, better stability．