Abstract: The conversion of ethylene glycol to glycolic acid by resting cells of Gluconobacter oxydans was investigated. Under batch conversion conditions,118. 5 g /L of glycolic acid could get from ethylene glycol after 30 h of reaction. The conversion was above 97%. The resting cells could successively convert three cycles. The average conversion was about 93. 3%. By fed-batch conversion,the yield can be further improved. Over 38h reaction,182. 5 g /L of glycolic acid was obtained,which greatly increased the product concentration in the conversion liquor.