NOVELTY - Biomass gasification, comprises adding the initial treated biomass feedstocks into pyrolysis furnace, carrying out thermal decomposition of biomass to obtain pyrolysis gas and carbon-containing tar; passing pressurized pyrolysis gas and air or oxygen-enriched gas into the bottom of the gasifier, mixing in pyrolysis gas nozzle and quickly burning, to generate carbon dioxide and high-temperature water vapor mixed gas; grinding the biochar, and injecting on top of the gasifier; and reacting the biochar with carbon dioxide and water vapor.    USE - The method is useful for biomass gasification (claimed).    ADVANTAGE - The method has gasification intensity, is suitable for large scale biomass gasification, and produces gasification product without tar content.    DETAILED DESCRIPTION - Biomass gasification, comprises (a) adding the initial treated biomass feedstocks into pyrolysis furnace, under external heat source or heat exchanger conditions, carrying out thermal decomposition of biomass to obtain pyrolysis gas and carbon-containing tar; (b) starting gasifier, passing pressurized pyrolysis gas and air or oxygen-enriched gas into the bottom of the gasifier, mixing in pyrolysis gas nozzle and quickly burning, to generate carbon dioxide and high-temperature water vapor mixed gas; (c) grinding the biochar, and injecting on top of the gasifier under pressure via pneumatic conveying way; (d) reacting the biochar with carbon dioxide and water vapor in the combustion zone, to generate carbon monoxide and hydrogen gas, which are passed out via gasification zone, and the adding the molten biomass ash into molten slag pool. An INDEPENDENT CLAIM is also included for separation device, for biomass gasification process, comprising a pyrolysis and combustion gasification regions, where the pyrolysis region includes feed inlet, pyrolysis furnace, grinding machine, lock hopper, discharge tank and pneumatic conveying device; and the combustion gasification region includes carbon black nozzle, pyrolysis gas nozzle, gasifier, outlet and slag pool; the feed inlet is connected to the pyrolysis furnace; and the pyrolysis furnace is connected to the mill and pyrolysis gas nozzle; the grinding machine is connected with the lock hopper, discharge bucket, pneumatic conveying device and charcoal nozzle; the gasifier comprises an upper portion, interconnecting with the inner and outer tube, where the inner tube is set in the combustion zone, for carrying out pyrolysis combustion reaction; and the gasification zone outer tube carries out biochar and pyrolysis gasification combustion; the outlet port is provided at the bottom of the outer cylinder; and the gasifier is connected to lower part of the molten slag pool.