Provided is a method of amplification of coke oven gas (COG) through reacting high-temperature carbon with carbon dioxide and/or water using waste heat generated in a coke oven. More particularly, a method of amplification of COG including providing a gasification agent including carbon dioxide, water, or a mixture thereof to a COG stream in a carburization chamber of a coke oven and gasifying carbon by allowing the gasification agent to react with carbon in the carburization chamber, and a coke oven apparatus suitable for the method are provided.