Method for continuously preparing polyether polyol with low unsaturation degree

The invention discloses a method for continuously preparing low-unsaturation polyether polyol, and belongs to the technical field of polyether polyol synthesis. The preparation method is characterized by comprising the following steps: introducing catalyst liquid generated by reaction of an initiator and a basic catalyst and an epoxy compound into a microchannel reactor for polymerization reaction, and then refining to obtain an intermediate; the method comprises the following steps: heating and degassing a double metal cyanide complex catalyst, acid and an intermediate in a closed container with a stirring function, uniformly mixing, and introducing the mixture and an epoxy compound into a micro-channel reactor group; and carrying out polymerization reaction on the intermediate and an epoxy compound to prepare the low-unsaturation polyether polyol. According to the preparation method, continuous operation can be carried out, the polymerization reaction is carried out while batching is carried out, compared w