Abstract: The joint strength of friction stir welding is an important indicator of performance.Through different combinations of welding parameters such as tool rotation rate,tool traverse speed and target depth,35 friction stir welded test plates of 7A52 aluminum alloy are prepared.The tensile strength of welded joints of the test plates is detected by tensile test.The regression model between the tensile strength of welded joints and welding process parameters is established.When the tool rotation rate n,the tool traverse speed v or the target depth deta individually changes,there is a peak of joint tensile strength.The tool rotation rate and the tool traverse speed interactively impact the tensile strength by means of n/v.It is proved that the optimized welding parameters can make joint tensile strength be up to 384.06 MPa.