The invention provides a garbage carbonization reacting system. The system comprises a reaction still, a reaction tank, a vapor generator and a control device, wherein the vapor generator is connected with the reaction still, and the vapor generator is used for supplying vapor to the reaction still; the reaction tank is used for placing garbage. When a reaction is carried out, the reaction tank is pushed into the reaction still to react to generate a carbonization mixture; after the reaction is completed, the reaction tank is pulled out of the reaction still. The reaction still comprises a still body and a still cover, wherein the still body is connected with the still cover in a sealing manner; the control device is connected with the reaction still, and the control device is used for controlling the change of the pressure and the temperature in the reaction still and the reaction time; a first guide rail which extends in the length direction of the still body is arranged in the still body. The system disclosed by the invention has the advantages that the structural scheme is reasonable, the device is advanced, the degree of automation is high, the investment cost of equipment is low, the occupation area of a required plant is small, and burning value of prepared biomass fuel is high, and the discharge is low.