The characteristics of the common boiling point of four furan (THF) aqueous solution with pressure change and THF and light, in the different boiling points of recombination, distillation of the process wastewater produced during the production of PBT was performed by using the three-tower distillation model of atmospheric pressure tower (dehydration tower) + Pressurized tower (light component tower) + atmospheric tower (off-recombination tower). The mass fraction of the distillate of the dehydration tower was about 93%, and the quality fraction of the top distillate and bottom product of the stripper was up to 91% and 98% respectively, and the distillation liquid of the tower was returned to the dehydration tower. The two Tata bottom distillate enters the three towers (reorganizes the tower) to remove the reorganization cent, Tetrahydrofuran (THF) Purity up to 99.99% 。