In the ethylene glycol production,the ratio of water and ethylene-oxide was 11.5∶1(mass ratio) in basic design. If the ratio was more,stream was more and the by-product of alcohol was less,the yield of ethylene glycol was more.If the ratio was less,the alcohol,for example diethylene glycol,was more.In production,besides ensuring the alcohol content must meet the standard,the best operation condtitions was less steam, lower reflux, and no useless-glycol in water in order to save energy.