The invention provides a method for synthesizing methyl-terminated triphenylethylene phenol polyoxyethylene ether in a microreaction system by using triphenylethylene phenol, ethylene oxide and methane chloride as raw materials. The microreaction system provided by the invention comprises a pre-treatment kettle, a micro-mixer, a preheating tube, a microreactor, a delay tube, a reaction kettle, a metering pump, a temperature control device, a back pressure valve, and the like. The microreactor is provided with a plurality of micro-channels; a microreaction unit is formed by the micro-mixer, themicroreactor and the delay tube. According to the method, the synthesis of polyether and an end-capping reaction are carried out in the microreactor, so that the reaction efficiency is greatly improved, the reaction time is shortened, and the product quality is improved. All reactions are completed in one system, so that the process is simple, and side reactions are few; the method can be used for commercial production.