Abstract :Diglycolic acid has been synthesized by the reaction of diethylene glycol and oxygen under heterogeneous conditions using water as solvent and Bi-Pt/C as catalyst.The structure of the product is confirmed by IR,1NMR spectra,etc.Effect of reaction temperature, volumes of solvents, amounts of catalysts , amounts of oxygen and reaction time have been studied.The optimum conditions are found as follows:reaction temperature 80℃,reaction time 8h, mass ratio substrate and catalyst 30,volume ratio water and substrate 30,oxygen flow 40ml/min.Under these conditions, the average yield of diglycolic acid is 95.0%.The catalyst can not be significant decreased in the terms of catalytic activity after six recycles.