A method for producing high-efficiency methanol capable of reducing emission of carbon dioxide. The method includes: a first step of preparing mixed gas by using steam and natural gas as raw materials and converting C2+ hydrocarbon contained in the natural gas into methane on a catalyst; a second step of preparing a synthesis gas including carbon monoxide, carbon dioxide, and hydrogen by reforming the mixed gas in a reformer filled with a reforming catalyst; and a third step of preparing methanol by using the synthesis gas as the raw material and reacting the synthesis gas.