The invention discloses a continuous technology for producing polycarboxylate superplasticizer monomer polyether through a one-step method. The technology includes the steps that with unsaturated alcohol or unsaturated alcohol ether or unsaturated amine as an initiator, epoxide polymerization is performed in a segmented mode in multiple reaction kettles at certain temperature and pressure under the action of a catalyst, and continuous synthesis is performed to obtain the product. The technology has the advantages that for synthesis of the polycarboxylate superplasticizer monomer polyether, by performing epoxide polymerization in the segmented mode in the multiple reaction kettles, the problem that one-step method production of high-molecular-weight products is difficult is solved; the continuous production technology thoroughly changes single intermittent kettle type production of such products, and continuous production improves the product production efficiency and increases the product yield; as the mode of using the special kettles for special purposes is formed, namely, each kettle is used for producing a fixed molecular structure with a fixed molecular weight of the product in a certain step, product quality stability is substantially improved, and technology and operation difficulty is lowered.