Abstract: Tar,a by-product in gasification process,has a great harm.In this paper,physical methods to remove tar in biomass gasification gas such as cyclone-separation,wet cleaning and dry cleaning are analyzed.Chemical conversion methods such as hightemperature pyrolysis and catalytic cracking are also discussed.Their advantages,disadvantages and application are compared.Treatment of tar in gasification gas is crucial for normal operation of biomass gasification gas engineering.