A test was carried out on an 6 MW industrial biomass atmospheric CFB gasifier in a power plant. The gas composition, NH3 and tar contents in the product gas at different temperatures were measured and analyzed. Ash (char in the present case) analysis was also made to make mass balance of chemical element in solid and gas phases during gasification based on Si balance analysis. The measurement results show that a gas productivity of 2 Nm3/kg (daf biomass) with gas LHV of 5MJ/Nm3 can be achieved at 750℃.The conversion of fuel-bound nitrogen (FBN) to NH3 ranges from 6 wt% to 70 wt% depending on temperature. Tar content in the product gas ranges from 2.5 to 16.7 g/m3. Small fractions of H, O, N, Cl and S contents in fuel remain in the ash while most of mineral metal element remains in the ash.