In this paper, the high-efficiency degradation and alcoholysis recovery of waste polyurethane foam were realized using a combination of a high-efficiency alkali metal catalyst (CsOH) and two-component mixed alcoholysis agents (glycerol and butanediol) in different proportions, using recycled polyether polyol and one-step foaming to prepare regenerated thermosetting polyurethane hard foam. The foaming agent and catalyst were adjusted experimentally to prepare regenerated polyurethane foam, and a series of tests were conducted on the viscosity, GPC, hydroxyl value, infrared spectrum, foaming time, apparent density, compressive strength, and other properties of the degradation products of the regenerated thermosetting polyurethane rigid foam. The resulting data were analyzed, and the following conclusions were drawn: The optimal conditions of alcoholysis were obtained when the mass ratio of glycerol to butanediol was 3:2, the amount of cesium hydroxide was 0.08%, the reaction temperature was 170 °C, and the reaction time was 2.5 h. Regenerated polyurethane foam with an apparent density of 34.1 kg/m3and a compressive strength of 0.301 MPa was prepared under these conditions. It had good thermal stability, complete sample pores, and a strong skeleton. At this time, these are the best reaction conditions for the alcoholysis of waste polyurethane foam, and the regenerated polyurethane foam meets various national standards.