A composition and a method for preparing the same are provided. The method for preparing the composition includes providing a polyethylene terephthalate waste. The polyethylene terephthalate waste is subjected to a depolymerization in the presence of a catalyst and an alcoholysis agent to obtain a mixture, wherein an oxidizing atmosphere is continuously introduced into the depolymerization. The mixture is subjected to a solid-liquid separation to obtain a solid. The solid is subjected to a purification to obtain the composition.