NOVELTY - A biomass pyrolysis of liquefied fuel oil comprises (A) biomass pre-treatment, (B) biomass pyrolysis, and (C) refining of bio-oil. The step (A) comprises putting biomass in soaking liquid and soaking for 30 minutes, where liquid surface is higher than biomass to remove dust; and drying biomass from which dust is removed so water content of biomass is dried less than 8 mass% of biomass. The step (C) includes obtaining heavy bio-oil by first stage of condenser and pre-heating heavy bio-oil to 400 degrees C and sending to fixed reactor.    USE - Method for biomass pyrolysis of liquefied fuel oil (claimed).    ADVANTAGE - The method removes dust, thus influence by the dust is reduced during pyrolysis, and yielding ratio of bio-oil is improved for 50-60%. The oxygen is transferred as fluid fuel with stability at normal temperature, thus providing high quality and high energy density.    DETAILED DESCRIPTION - Biomass pyrolysis of liquefied fuel oil comprises (A) biomass pre-treatment, (B) biomass pyrolysis, and (C) refining of bio-oil. The step (A) comprises using water, hydrochloric acid (5 mol/L) and hydrofluoric acid to prepare soaking liquid at vol. ratio of 20:1:0.5; putting biomass in soaking liquid and soaking for 30 minutes, where liquid surface is higher than biomass to remove dust; drying biomass from which dust is removed so water content of biomass is dried less than 8 mass% of biomass; and cutting dried biomass into sections of 3-5 mm. The step (B) comprises:    (A) conveying cut biomass to fluidized bed;    (B) adding material at speed of 20-200 kg/hour;    (C) performing pyrolysis under anaerobic condition at 500-650 degrees C;    (D) regulating gas carrying speed; controlling retention time of gas after pyrolysis at 0.8-1.2 seconds;    (E) when gas after pyrolysis leaves, sending biomass to cyclone separator;    (F) separating carbon by centrifugal action;    (G) sending steam to a condenser, where condensable part is cooled by two stages of condensers to form liquid; and    (H) introducing liquid to oil-water separator to separate oil and water, and obtaining bio-oil, where incondensable part is purified by filter and is sent to gas kettle.    The step (C) includes:    (A) obtaining heavy bio-oil by first stage of condenser, with density greater than 1.0-1.5 g/cm3;    (B) obtaining light bio-oil by secondary stage of condenser, with density of 0.8-1.0 g/cm3;    (C) performing catalytic pyrolysis for obtained heavy bio-oil;    (D) pre-heating heavy bio-oil to 400 degrees C and sending to fixed reactor;    (E) keeping temperature at 410- 490 degrees C, where catalyst is shape selective catalysis ZSM-5, Na-ZSM-5, HZSM-5 or aluminum phosphate molecular sieve; and controlling feeding ratio at 3-6 m3/hour based on size of the device, where dosage of catalyst is 2% of bio-oil; and performing catalytic pyrolysis for bio-oil.