The invention discloses a system and method for disposing household garbage. The system comprises a pretreatment unit, a pyrolysis device, a carbon dioxide gathering unit, a first energy-saving deacidification device and a methanol synthesis unit. The pretreatment unit is provided with a household garbage inlet, an organic garbage outlet and an inorganic garbage outlet. The pyrolysis device is provided with an organic garbage inlet, a high-temperature pyrolysis oil gas outlet, a pyrolysis carbon outlet and a pyrolysis tail gas outlet. The carbon dioxide gathering unit is provided with a tail gas inlet and a carbon dioxide gas outlet. The first energy-saving deacidification device is provided with a high-temperature pyrolysis oil gas inlet, a carbon dioxide gas inlet, a cooled and deacidified pyrolysis oil gas outlet and a preheated carbon dioxide gas outlet. The methanol synthesis unit is provided with a hydrogen inlet, a preheated carbon dioxide gas inlet and a methanol outlet. By the adoption of the system, reduction treatment on household garbage can be achieved, CO2 in pyrolysis tail gas is used as a raw material for preparing methanol, and accordingly greenhouse gas CO2 emissions are reduced while resource utilization of household garbage is achieved. The system is particularly applicable to technology promotion and large-scale production.