The utility model discloses a biomass particle combustor comprising a feeding device, an air supplying device and a combusting furnace. The feeding device comprises a cylinder, a hopper connected onto the inner wall of the cylinder and a worm feeder mounted below the hopper, wherein the worm feeder is connected with the hopper via a hopper connector, and a discharging pipe is arranged at the discharging end of the worm feeder and connected with a feeding pipe of a hearth. The air supplying device comprises an air blower and an air supplying pipe which are mounted below the worm feeder, and the air supplying pipe is connected to an air supply of the hearth. The combusting furnace comprises an outer bushing, the hearth, a hearth inner bushing, an electrical igniter, a fire outlet pipe and a fire outlet pipe connection cover. The biomass particle combustor is characterized in that oxygen is preheated via a preheating oxygen supply air flue between the hearth inner bushing and the outer bushing, the preheating oxygen supply air flue is communicated with an air inlet pipe which is communicated with the air supply, a movable grate bridge is arranged at the bottom of the hearth, and opening and closing of the grate bridge are controlled by a grate bridge controlling rod.