The invention relates to the technical field of biomass fuel burning, in particular to a biomass burning machine provided with a tubular furnace hearth. The biomass burning machine comprises a stock bin, a feeding mechanism, the tubular furnace hearth and a slag discharging and breaking device, and is characterized in that a detachable lengthened barrel (2) is arranged at the top of the stock bin, a stock bin cover (1) is mounted at the top end of the lengthened barrel (2) in a sleeving manner, and a hopper (4) is arranged in a barrel (3); the feeding mechanism comprises a feeding casing (6) and a feeding screw rod (7), the feeding casing (6) penetrates through a bellows (8) and is movably mounted at a bottom outlet of the hopper (4), and the feeding screw rod (7) is arranged in the feeding casing (6); and the slag discharging and breaking device comprises a slag discharging and breaking screw rod (9) provided with a hollow part as well as a chain wheel (10). The biomass burning machine provided with the tubular furnace hearth has the advantages of sufficient burning, low tail gas pollution, prevention of slag bonding and caking, wide biomass fuel adaptability, long service life, stable operation, low maintenance cost and the like.