This paper studies the influence of oxide film on the performance of 6005 A-T6 aluminum alloy BT-FSW joints through the analysis of tensile test,bending test and microstructure. Without removing off oxidation film,the joint produces the C-shaped S line.The tensile strength of the joint is 184.3 MPa,72.2% of the strength of the parent material. The bending of the joint is not qualified.With removing off oxidation film, the joint does not show an obvious S line. The joint is divided into WNZ,TMAZ,HAZ and BM. The tensile strength of the joint is 219.3 MPa,86% of the strength of the parent material. The bending of the joint is qualified.