The invention relates to a system for making coal gas and activated carbon with sorted garbage as the raw material and device and method thereof, which effectively treats and utilizes the biomass raw material in the garbage. The system adopts the technical scheme that the system comprises a biomass raw material pretreating system, a cracking system, a coal gas collecting system, a gaseous isolate collecting and circulating system and an activated carbon finishing processing and treating system; garbage raw material is crushed in the pretreating system and then enters the cracking system, the gaseous resultant generated from the cracking system is treated through the gaseous isolate collecting and circulating system and then conveyed to the corresponding circulating inlet of the system, and a charring furnace device for microwave heating and enclosed low-temperature cracking is adopted in the cracking system. The invention fully utilizes the garbage resources, reduces environment pollution and energy consumption, and fundamentally realizes harmless garbage treatment.