The ER5356 welded wire was welded under the TIG welding to 5 mm thick 7075-T6 super hard aluminum. The performance and microstructure of the welded joints obtained under different welding processes were analyzed, and the best welding parameters were determined. After solid solution treatment for the specimens, four solid solution temperature and three solid solution time were selected for the experiment. The change law of microstructure and properties of welded joints under different solid solution parameters was studied through macro morphology and metallographic observation, scanning electron microscope, X ray diffraction analysis, tensile test and hardness measurement. The results show that the best welding current is 110 A determined by welding technology, solid solution treatment temperature is 480 ℃, solid solution time is 45 min. At this time, the microstructure of welded joints is improved, and the mechanical properties of the welded joints are better. That is, the size of the grain structure is homogeneous, and the precipitates are dispersed in the matrix and grain boundaries. Thus, more elements are dissolved into the matrix and the grain boundary.