A gasification-liquefaction disposal method, system and equipment for MSW are disclosed. The method involves the MSW pretreatment of dehydrating and separating, thus reducing water and inorganic substance content of the waste. Then, the MSW is introduced into a plasma gasifier (23) by a carbon dioxide air-sealed feeding device (13) and gasified therein to obtain hydrogen-rich syngas. The hydrogen-rich syngas is then cooled, deacidified, dedusted and separated to obtain carbon dioxide. Then, the hydrogen-rich syngas is catalyzed to produce methanol product in a methanol synthesis reactor (52). The separated carbon dioxide is sent back to a carbonation reaction chamber (2007) of a gasification system to perform carbonation reaction with calcium oxide, thereby releasing heat to provide assistant heat energy for gasification and avoiding greenhouse gas from being discharged into environment. Exhaust gas is returned to the plasma gasifier (23) for remelting treatment, thus forming a closed-loop circulation production system and realizing the disposal of the MSW with zero discharge and no pollution, thereby avoiding dioxin pollution and converting the MSW to chemical raw materials and fuel needed by mankind. The method, system and equipment are suitable for harmless and recycling disposal of MSW, industrial high polymer waste, composting waste and waste in waste sorting sites.