In order to solve the problem of environmental pollution of waste polyethylene terephthalate (PET) caused by waste polyester, we used the mixed depolymerization of alcohol and water instead of the traditional hydrolysis method.The effects of temperature, ratio of alcohol to water, reaction time, concentration of alkali and volume of solvent on depolymerization of waste polyester were investigated by orthogonal experiment.Experimental results show that Select polyester quality 2.5 grams of the condition the degradation of mixed alcohol water temperature between 75 ℃ to 78 ℃, 7:1 alcohol water ratio, reaction time in about two hours, the mass fraction of alkali is 16%, solvent volume of 40 ml, as depolymerizing effect is best.