The invention provides a method for preparing methyltris(methylethylketoxime)silane. The method comprises the following steps that: a. methyl trichlorosilane, butanone oxime, alkaline air and 120#solvent naphtha are simultaneously pumped in a reaction kettle by a measuring pump and reacted for 30m under the normal pressure and at a temperature of between 35 to 40 DEG C, and reactants are picked up and filtered by a centrifuge so as to obtain a filtrate and ammonium chloride deposit; b. the filtrate passes through a falling-film evaporator to distill off 120#solvent naphtha, and the coarse product of methyltris(methylethylketoxime)silane is obtained; c. the coarse product of methyltris(methylethylketoxime)silane is put in a scraper evaporator for distillation, the remained butanone oxime is distilled off, and the refined product is obtained. The process of the invention has the characteristics of big productivity, low energy consumption, simple control and greenness and environmental protection, etc.; moreover, the product yield is 95 percent, the effective content of the product is high, and the content of methyltris(methylethylketoxime)silane is more than 96 percent.