A
biomass burner comprises a furnace, a filling port, a
slag removal port and an ash cleaning port. The filling port, the
slag removal port and the ash cleaning port are arranged in the front side face of the furnace from top to bottom, a filling port opening and closing mechanism, a
slag removal port opening and closing mechanism and an ash cleaning port opening and closing mechanism are arranged on the filling port, the slag removal port and the ash cleaning port correspondingly, and grates are arranged in the furnace. A circular secondary air duct with a secondary
tuyere is arranged on the side face of the furnace body, the inner circular wall of the secondary air duct forms a secondary
air cavity communicated with the inside of the furnace, and burning units communicated with the secondary air duct are arranged in the secondary
air cavity. A fire outlet communicated with the secondary
air cavity is arranged at the outer end of the secondary air duct. The
biomass burner is simple in structure, a large amount of fuel can be stored above the grates inside the furnace at one time, sustained burning time can be prolonged greatly, and fuel types are unlimited; by means of secondary air distribution of the burning units,
oxygen needed during fuel burning can be supplemented effectively, and fuel burning heat efficiency and fuel
utilization rate are increased greatly.