NOVELTY - System comprises an active carbon producing subsystem and a biomass pyrolysis subsystem. The active carbon producing subsystem comprises a stirring device, a drying device, a carbonizing device and a first activating device. The biomass pyrolysis subsystem comprises a heating device for heating the biomass pyrolysis furnace with the combustion biomass or biomass pyrolysis gas, and an afterheat boiler composed of a first heat exchange pipeline. The biomass pyrolysis furnace is useful for pyrolysis of the biomass by heat from heating device to generate high temperature biomass pyrolysis gas.    USE - The system is useful for heating with biomass and producing activated carbon with coal ash.    ADVANTAGE - The system achieves maximum utilization of the resources by completely utilizing the heat and combustible gas from the biomass pyrolysis.    DETAILED DESCRIPTION - System comprises an active carbon producing subsystem and a biomass pyrolysis subsystem. The active carbon producing subsystem comprises a stirring device, a drying device, a carbonizing device and a first activating device. The biomass pyrolysis subsystem comprises a heating device for heating the biomass pyrolysis furnace with the combustion biomass or biomass pyrolysis gas, and an afterheat boiler composed of a first heat exchange pipeline. The biomass pyrolysis furnace is useful for pyrolysis of the biomass by the heat from the heating device to generate the high temperature biomass pyrolysis gas. The first heat exchange pipeline is composed of a first gas inlet and a first gas outlet. The biomass pyrolysis furnace transfers the high temperature biomass pyrolysis gas to the first gas inlet by the first pyrolysis gas pipeline. The first gas outlet is connected to the second pyrolysis gas pipeline. The afterheat boiler transfers the cooled biomass pyrolysis gas to the heating device by the second pyrolysis gas pipeline.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of the system for heating with biomass and producing activated carbon with coal ash.