KOH is used as a catalyst. The synthesis of a high molecular weight (relative molecular mass) hydrophilic polyether was carried out. One is to synthesize 1000 molecular weight (relative molecular mass) from the initiator, and then directly synthesize the product (original production process), and then carry out refining treatment by pipetting; the other is to synthesize 1000 molecular weight from the initiator. Molecular mass), further processing in the subsequent synthesis, when the molecular weight reaches 4000 (relative molecular mass), the curing degassing treatment is carried out, and after completion, the mixture of ethylene oxide and propylene oxide is continuously continued to synthesize the product (new production process) ), the synthesis is finished, and after aging, the liquid is pipetted to be refined. The results show that the quality of the new process product is improved, the yield of hydrophilic polyether is improved, and the waterproof effect is improved to 25%; the molecular weight of the old process is not up to the designed molecular weight, and the yield of hydrophilic polyether is lower and the waterproof application effect is less than 25%.