The invention discloses a preparation method of 3-[(3, 3-dimethoxy-2, 7-dioxa-3-
silane-9-yl) oxy]
propionitrile, which comprises the following steps: 1, adding 3-[(2-hydroxyethyl) oxy]
propionitrile and a first
organic solvent, cooling to 0-5 DEG C, adding
sodium hydride in batches under the protection of
nitrogen, heating to
room temperature, stirring for 0.5-1 hour, controlling the temperature
not to exceed 25 DEG C, dropwise adding bromopropene, reacting for 1-2 hours, cooling to 0-5 DEG C, cooling to 0-5 DEG C, cooling to 0-5 DEG C, cooling to 0-5 DEG C, cooling to 0-5 DEG C, adding
sodium hydride in batches under the protection of
nitrogen, heating to
room temperature, stirring for 0.5-1 hour, and cooling to 0-5 DEG C to obtain a second
organic solvent; after dropwise adding, filtering to remove insoluble substances, carrying out rotary
evaporation to remove the
solvent, and rectifying a crude product to obtain 3-{[2-(prop-2-alkenyl oxy) ethyl] oxy}
propionitrile; and 2, adding 3-{[2-(propyl-2-alkenyl oxy) ethyl] oxy} propionitrile and a
hydrosilylation catalyst, heating to 130-150 DEG C, dropwise adding
trichlorosilane, carrying out a
thermal reaction for 10-15 h after dropwise adding, dropwise adding a
methanol solution dissolved with an acid-binding agent while controlling the temperature to be 10 DEG C or below, and carrying out molecular rectification treatment on a crude product after the reaction is completed to obtain a finished product. The method has the advantages that the synthesis method is simple and easy to implement, the post-treatment method is easy to operate, and the product purity is high.