The invention provides a serial process for synthesizing glycol and co-producing methyl carbonate with CO as starting raw material. The major process is carried out under the condition of gas phase: firstly, CO and methyl nitrite are carried out gas-phase oxidation coupled reaction to synthesize dimethyl oxalate and methyl carbonate; subsequently, methyl carbonate is separated out by a distillingtower, and heavy component dimethyl oxalate is processed by catalytic hydrogenation to obtain glycol. Methyl nitrite consumed during the oxidation coupled reaction can be supplemented by a regeneration tower (NO, O2 and methanol synthesis methyl nitrite. The main raw materials consumed in the process are inexpensive CO, O2, H2, methyl alcohol and the like, while the products of the process are glycol and methyl carbonate with high added value. The process is applicable to industrial production.