Butt welding of LF6 aluminum alloy is carried out by two different welding methods,A-TIG welding and TIG welding. ATIG welding using small current,but TIG welding using large current,then use metallographic analysis,tensile fracture scan,EDS analysis and electron probe element analysis to analyze the differences between microstructure,mechanical properties and element distribution of welded joints. The test results show that the microstructure of A-TIG welding is thicker than that of TIG welding and the hardness of the weld is higher. The tensile performance of A-TIG welded joint is higher than that of TIG welding. The EDS analysis and the electron probe element analysis respectively on the heat affected zone and weld area of A-TIG welding and TIG welding are carried out respectively. The analysis data show that the influence of the two welding methods on the heat affected zone and the weld area element is almost undifferentiated.