The invention relates to a polyether-type refining agent and its preparation method and belongs to the technical field of preparation of surfactants in organic chemistry. The refining agent is prepared by polymerization of saturated fatty alcohol, oxirane and epoxypropane which are used as raw materials under the action of a perchlorate catalyst. By the use of the polyether-type refining agent prepared by the above method, rapid product penetration is ensured, a finished product has low foam, and emulsifying ability of a product is high. In addition, low-temperature fluidity of the refining agent is excellent, and the refining agent has a good refining effect.