NOVELTY - A dry biomass fuel gas making method comprises: (a) preparing materials: selecting block biomass material; (b) charging: adding biomass material in biomass fuel gas making furnace; (c) making gas: adding gas making material in furnace; (d) dedusting: removing ash by cyclone dust removal; (e) heat exchanging the finished fuel gas in a condenser (12); (f) separating gas, oil and water: letting the condensed medium remain on the bottom of the gas liquid separation tower; (g) detarring by electric tar precipitator; and (h) sending the top quality fuel gas in low pressure steel gas cabinet (26).    USE - The method is useful for making a dry biomass fuel gas (claimed).    ADVANTAGE - The invention has no sewage. Moreover, it stops production phenomenon caused by pipe blockage that cannot be appeared in the running of the whole machine set; the labor intensity of operator can be lightened largely; and the produced top quality fuel gas whose tar quantity does not exceed 10 mg/Nm3, where the tar content of biomass fuel gas cannot exceed 50 mg/Nm3. Additionally, its new-typed dry biomass fuel gas making machine set can be used with gas making furnace having gas yield in each hour of 500-3000 Nm3/hour, with new-typed structure. The centralization of supply gas can be enlarged to wider range.    DETAILED DESCRIPTION - A dry biomass fuel gas making method comprises: (a) preparing materials: selecting block biomass material; (b) charging: adding biomass material into a biomass fuel gas making furnace; (c) making gas: adding the gas making material into the biomass fuel gas making furnace and thermalizing, producing mixed fuel gas that enters into a dedusting system from a fuel gas outlet (11); (d) dedusting: removing the ash that is 50-80% of the mixed fuel gas and obtaining the fuel gas under the effect of cyclone dust removal, where the removed ash enters into an ash storage box (6), purifying the fuel gas continuously by a purification tower, obtaining the finished fuel gas; (e) heat exchanging: heat exchanging the finished fuel gas in a condenser (12) to analyze the fuel gas temperature on the outlet of the condenser at 35-45 degrees C, where the condensed water, tar and clean finished fuel gas enter into a gas liquid separation tower (14); (f) separating gas, oil and water: letting the condensed medium remain on the bottom of the gas liquid separation tower discharging periodically according to operating instruction, where the clean biomass fuel gas enters into the electric tar precipitator (16); (g) detarring by electric tar precipitator; and (h) sending the top quality fuel gas to a low pressure steel gas cabinet (26) from a condenser cylinder (27) by a Roots blower (19) to be used by a user.    DESCRIPTION OF DRAWING(S) - The drawing shows a side view of the biomass fuel gas making furnace.    Storage box (6)    Fuel gas outlet (11)    Condenser (12)    Gas liquid separation tower (14)    Electric tar precipitator (16)    Roots blower (19)    Low pressure steel gas cabinet (26)    Condenser cylinder (27)