The invention discloses a preparation method of a fluorine-silicon surfactant. The method comprises the following steps of: continually dripping 13 to 18 weight parts of trichlorosilane into 44 to 65 weight parts of perfluor alkyl ethylene or perfluor alkyl ethyl iodide serving as a raw material in the presence of 0.1 to 1.0 weight part of noble metal catalyst so as to obtain an intermediate product; and adding 14.8 to 20 weight parts of high-boiling-point solvent into the intermediate product, continuously dripping 10 to 16.35 weight parts of methanol or ethanol for reacting, decompressing and rectifying so as to obtain a target product. In the method, raw materials are readily available, byproduct is not produced, a reaction in an entire synthesis process is stable, process control is stable, safety, low cost and easy separation are realized, the yield of a final fluorine-silicon surfactant is over 95 percent, and the purity of the surfactant is over 98 percent. Due to the presence of a siloxane active group, the fluorine-silicon surfactant can react with and be tightly combined with substances with a hydroxy functional group, such as glass and the like, so that the surface of the fluorine-silicon surfactant has high waterproofness, oil resistance and soil resistance, surface tension is less than 17.6 dynes per meter, and light transmittance is over 99.9 percent.