Polyether polyol (polyether for short) is prepared by adding polymerization reaction of starting agent (compound containing active hydrogen group) with ethylene oxide (EO), propylene oxide (PO), butane oxide (BO) and so on in the presence of catalyst. Polyether polyol is often used in the manufacture of universal polyurethane foams, adhesives and elastomers. Special polyether polyols are also used as defoaming agents, surfactants, etc.