The invention relates to a method for producing alkoxylate through a microchannel reactor, and discloses a method for continuously performing alkoxylation reaction in a microreactor. According to the invention, initiator potassium alcoholate in which low molecules (the low molecules herein are mainly water and methanol) are removed and epoxide enter a microreactor, a delay line and a mixer in a liquid-phase form to perform liquid-liquid reaction, the purpose of sufficient mass transfer and heat transfer is achieved, and the liquid-liquid reaction is realized by increasing the pressure of the reaction system and adding a counterbalance valve. Compared with the alkoxylation reaction in the prior art, the method can effectively solve the heat transfer problem of such reaction, realizes fast and uniform mixing and constant reaction temperature, avoids the temperature runaway phenomenon and reduces the side reaction; the process is continuous flow reaction, and the reaction time is shortened to a few minutes, thus obviously improving the reaction efficiency and production efficiency; and the microreactor hardly has scale-up effect and is high in safety performance, thus being suitable for industrial production.