These Experiments were performed to synthesize the polyethylene Terephthalate. In the reaction, it is necessary to remove excess glycol during the polycondensation reaction for a long periode without catalysts. To accelerate both the ester exchange and the polycondensation reaction, catalysts are introduced. The experiment shows that, usually, in the cases of metalic oxides as catalyst, the larger the amount of the catalyst, the shorter is the reaction time. Too high a concentration of litharge-monooxide-, However, courses the formation of colored by-products. To produce completely white product, the concentration of litharge should not be larger than 0.02%, based on the weight of dimethyl terephthalate. And in a recent disclosure, Metalic Acetate, such as lead acetate, Zinc acetate, and Magnesium acetate, is claimed to accelerate both the ester exchange and polycondensation reaction without producing discoloration. In amounts ranging from 0.05% to 0.06% based on the weight of dimethyl terephthalate, used by itself, these catalysts are particulary suitable for producing fiber-forming polyethylene terephthalate.