The utility model relates to biomass-energy combustion equipment, in particular to a biomass-energy circulating fluidized bed boiler with low energy consumption. The fluidized bed boiler comprises a hearth, a fluidized bed combustor, a separator, a material return system and a vertical shaft flue, wherein the upper part of the hearth is connected with the separator; the lower part of the separator is connected with the combustor through the material return system, while the upper part is communicated with the vertical shaft flue; a superheater, an economizer and an air preheater are sequentially distributed in the vertical shaft flue; the separator is a heat insulated cyclone separator, an outlet center tube is offset, and the lower part is provided with a self-balancing material return valve; and the hearth is a membrane type water-cooling wall hearth and internally distributed with a water cooling panel. With the biomass-energy circulating fluidized bed boiler, biomass energy can be completely combusted, the usage of combustion-supporting coal only accounts for 10%-20% total quantity of the fuel entering the boiler, and the electricity consumption of a primary air fan is reduced by 20%-30%. The tail vertical shaft flue is completely welded and sealed with a steel panel structure, thus reducing air leakage rate and improving efficiency; and the design of the water cooling panel leads the combustion temperature in a main circulating loop to be kept at a relatively low level, thus avoiding the slagging problem of fluidized bed materials resulted from low ash fusion point of the biomass energy.