NOVELTY - Fine grains of biomass raw material are put into spiral pyrolysis reactor, and pyrolyzed to obtain biomass pyrolyzed gas and pyrolyzed residual coke. The pyrolyzed residual coke is rapid-pyrolyzed in shallow fluidized bed, to produce pyrolyzed gas containing low molecular phenol and pyrolyzed solid rich in cellulose and lignin. The condensable gas in the pyrolyzed gas is condensed to obtain pyrolyzed low molecular phenol. The pyrolyzed solid is rapid-pyrolyzed, dust is removed, and the purified pyrolyzed gas is condensed in spray tower, to obtain biological oil.    USE - Preparation of biological oil and chemicals such as phenol, aldehyde and organic acid e.g. acetic acid.    ADVANTAGE - The method provides high-quality biological oil having low moisture content and excellent storage stability.    DETAILED DESCRIPTION - Fine grains of biomass raw material are put into a spiral pyrolysis reactor, and pyrolyzed at 200-280 degrees C to obtain biomass pyrolyzed gas and pyrolyzed residual coke. The pyrolyzed gas is collected, condensed and dehydrated to obtain aldehyde and organic acid. The pyrolyzed residual coke is put into a shallow fluidized bed, rapid-pyrolysis is carried out at temperature of 300-350 degrees C and air flow rate of 0.1-0.5 m/second to produce pyrolyzed gas containing low molecular phenol compound and pyrolyzed solid rich in cellulose and lignin. The pyrolyzed gas containing low molecular phenol compound is subjected to gas-solid separation in the built-in cyclone separator of shallow fluidized bed, and the condensable gas of pyrolyzed gas is condensed in condensing tower to obtain pyrolyzed low molecular phenol. The pyrolyzed solid is put into a deep fluidized bed from the solid outlet at mid-upper portion of dense phase area of shallow fluidized bed, rapid-pyrolysis is carried out at temperature of 450-600 degrees C and air flow rate of 0.5-1 m/second, complete-pyrolysis is carried out in fluidized bed under high temperature, and then the pyrolyzed gas is released from the gas outlet provided at top of deep fluidized bed. Dust is removed from the pyrolysis gas flown from the gas outlet at the top of deep fluidized bed by a cyclone separator, and the pyrolysis gas is purified. The pyrolysis gas is sprayed into a spray tower, condensed, and the gas is stored in a biological oil collection tank. The spraying solution in the spray tower is produced by extracting the biological oil collected in the biological oil tank with oil pump and cooling the biological oil in heat exchanger. The spraying solution is recycled for further process. The small oil droplets which are not collected in the spray tower is passed out together with the uncondensed pyrolyzed gas to a pyrolysis gas filter from the gas outlet at the top of spray tower, filtered and collected. The collected biological oil is put into the biological oil collection tank. The filtered pyrolysis gas, uncondensed pyrolysis gas from the gas outlet of condensing tower and pyrolysis residual carbon collected by the dust hopper of cyclone separator are introduced into a combustion chamber, and complete combustion is carried out to produce high-temperature smoke. Dust is removed from the smoke to purify, and a portion of smoke is passed as pyrolysis heat source to the external heating gas inlet of spiral pyrolysis reactor. The remaining portion of smoke is passed as pyrolysis heat source and fluidizing gas to the smoke inlets of shallow-and-deep fluidized bed. Thus, the biological oil and chemical are prepared by pyrolysis of biomass. An INDEPENDENT CLAIM is included for device for preparation of biological oil and chemicals, which comprises spiral pyrolysis reactor, shallow fluidized bed, deep fluidized bed, combustion chamber, condensing tower, cyclone separators, spray tower, biological oil collection tank and pyrolysis gas filter. The spiral pyrolysis reactor has a material feeding hopper at front end, a pyrolysis gas outlet and a pyrolysis residual coke outlet at rear end, a spiral propeller shaft and a heating sleeve. The pyrolysis residual coke outlet of pyrolysis reactor is connected to the material inlet of shallow fluidized bed through star-shaped material discharging valve and spiral material feeder. The lower side of shallow fluidized bed has high-temperature smoke inlet. The mid-lower portion of shallow fluidized bed has solid product outlet, and the mid-upper portion of shallow fluidized bed has built-in cyclone separator. The lower portion of deep fluidized bed has air distributing plate and high-temperature smoke inlet. The upper portion of deep fluidized bed has gas outlet connected to the spray tower through the cyclone separator. The lower portion of spray tower is connected to the biological oil collection tank. An oil spraying device comprises an oil pump, and the heat exchanger is connected between the spray tower and biological oil collection tank. The pyrolysis filter is connected with the gas outlet at the upper portion of spray tower. The combustion chamber has pyrolysis material inlet, air inlet and high-temperature smoke outlet. The pyrolysis material inlet is separately connected to the gas outlet of pyrolysis gas filter, gas outlet of condensing tower, and hopper material outlets of cyclone separators.