The invention discloses a biomass gas burner, and is applied to the technical field of burners. The biomass gas burner comprises an igniting gun and a burner body which is arranged on a heat storage chamber, wherein the burner body comprises an inner shell, a middle shell and an outer shell; an inner air inlet is formed in the inner shell; an inner air distribution chamber is formed by the interior of the inner shell; a biomass gas inlet is formed in the middle shell; a gas chamber is formed between the middle shell and the inner shell; an outer air inlet is formed in the outer shell; an outer air distribution chamber is formed between the outer shell and the middle shell; a burning ejection nozzle is formed at the front end of the gas chamber; a burning area 1 is formed in a position of the inner side of the burning ejection nozzle of the burning chamber; a burning area 2 is formed at the burning ejection nozzle; a burning area 3 is formed in the heat storage chamber; and an inner air distribution port is formed in the front end of the inner air distribution chamber. The biomass gas burner also comprises a primary air distribution pipe which can lead air current in the outer air distribution chamber into the burning area 1 and a secondary air distribution pipe which can lead air current in the outer air distribution chamber into the burning area 2. By adoption of staged combustion and three-level mixing, the burner can realize low-oxygen air distribution and low nitride emission.