[Objective] The effect of the gasification temperature under the different atmospheres on the component of syngas from tar and the characteristics of syngas formation was researched.[Method] The component and the characteristics of the syngas produced from the gasification of tar through the biomass pyrolysis at different temperature of 500,600,700,800 or 900 ℃ was studied in a fixed bed reactor of different agents: N2,water atmospheres and CO2 in Lab.[Results] Under the reactor of three agents: N2,water atmospheres and CO2,the concentration and gasification characteristics of H2,CO and CH4 was improved with the temperature-increasing.The introduction of water steam would obviously improve the concentration of H2 and CO in the produced gas and the concentration of H2 would reach the maximum(45.22%) at 800 ℃.The high concentration of carbon dioxide had great inhibition effect on the gasification of tar.[Conclusion] The important theoretic reference for the utilization of the gasification of tar and its good-quality was provided.