The polyester polyol was prepared by depolymerizing polyethylene terephthalate(PET) using catalyst with single step depolymerization technology in ordinary pressure,rigid polyurethane foam was prepared by using the polyester polyol with physical foaming method,to achieve the purpose of recycling of used PET.The hydroxyl,acid and viscosity of the polyester polyol as the response value.Dosages of catalyst and alkali，pyrolysis time were chosen as principal factors,and the optimized conditions for alcoholysis of PET were obtained with using response surface methodology(RSM) were as follows:catalyst Sb2O3 0.3% of PET weight,alcoholysis agents diglycol(DEG) 100% of PET weight,reaction time 2.5 hours.The experimental verification indicated that the conditions by RSM analysis were reliable,the hydroxyl value,acid value and viscosity of the product were 503.9 mgKOH/g,2.4 mgKOH/g and 1310 mPa·s,respectively.Rigid polyurethane foam is made with the polyester polyol,its coefficient of thermal conductivity is 0.02～0.03 W/(m·K) and density is 40～50 kg/m3,it shows that the recycling of used PET can be achieved through this method,and its recycling value was improved.