The invention provides a biomass fuel heat supply system. The heat supply system comprises a biomass furnace and underfloor heating coil pipes, wherein the biomass furnace communicates with the underfloor heating coil pipes through a water feeding pipe and a water return pipe. The biomass furnace comprises a first combustion chamber and a second combustion chamber communicating with the first combustion chamber; the bottom of the first combustion chamber is provided with a fire grate, the portion under the fire grate is divided into a combustion area and a combustion ash area, the tops of the combustion area, the combustion ash area and the second combustion chamber are connected with air discharging pipes, the top of the second combustion chamber is connected with a flue gas discharging pipe, and the air discharging pipes of the combustion area, the combustion ash area and the second combustion chamber are jointly connected with an air feeding pipe, and the air feeding pipe and the flue gas discharging pipe form a gas heat exchanger. The biomass fuel heat supply system has the advantages of being capable of saving energy, low in discharging quantity, free of pollution, prone to operation and control and high in automation.