Abstract: Welding 5 mm thick 6061-T651 aluminum alloy with laser-TIG composite heat source filler wire, investigate the influence of arc current on weld formation of composite filler wire welding , analyzed the weld microstructure and microhardness characteristics under the optimized process parameters,and compared with single TIG filament welding. The results show that the use of laser-TIG arc composite heat source filler wire welding of 6061-T651 aluminum alloy can effectively improve the weld formation; when the TIG arc current is 140 A, the welding process is stable and the welding seam forming effect is good; the microstucture in the center area of the composite filler wire weld is equiaxed, and the fusion zone is compo sed of a large number of dendrites; the microhardness of composite filler wire welding is higher t han that of single TIG filler wire welding, there is a softening phenomenon in the weld area,within the range of selected test points, the average hardness of the weld center of the composite filler wire welding is 66.91 HV, which is about 62.0% of the hardness of the base material, which is about 13.1% higher than the microhardness of the TIG filler wire welding alone.