Abstract: In the face of the challenge of manufacturing lightweight structures for aircraft, a composite manufacturing process of integral wall panels using friction stir welding/superplastic forming was proposed. The experimental research on the mechanical properties, macroscopic morphology and microstructure of 2195 alumi-num lithium alloy thin plate lap friction stir welding joints under different process parameters was conducted. The results show that different process parameters have different heat inputs during the welding process. The complex thermal mechanical effect affects the effective overlap width of the interface and ultimately affects the mechanical properties of the joint. Different combinations of process parameters can affect the formation of interface defects, among which the height of Hook defects is mainly related to the relative motion speed of the tool and advancing side material. The higher the relative motion speed, the higher the height of Hook defects, and the effect of defects on the mechanical properties of the joint is not significant. When the rotational speed is 1200 r/min and the welding speed is 100 mm/min, the effective lap width of the joint is maximum and it has the best mechanical properties. Its maximum fracture load is 3.41 kN, and the tensile strength is 363 MPa, reaching 75% of the base material performance.