Based on much hydrogen and less carbon in carbon filling technology of coke oven gas making methyl alcohol, production capacity still needs promotion, selection of the carbon source and filling carbon technology were compared, combined with the actual situation of Hebei Fengfeng Coal Coking Corporation Ltd., liquid CO₂ was taken as the carbon filling source, direct carbon filling before transformation was adopted. System running data and effect application before and after technology transformation were compared and analyzed, the result showed that hydrogen-carbon ratio of carbon filling device making methyl alcohol got closer to the theoretical value, improved the methanol production and economic benefit, increased 1.15 155 million yuan a year.