A7N01 aluminum alloy with the thickness of 4 mm is welded by using fiber laser-variable polarity TIG hybrid welding with filler wire. The effects of both welding current and welding speed on weld formation and porisities are discussed. The microstructure and mechanical properties of the joint obtained at optimal welding parameters are investigated. Experimental results show that the top weld width increases and the bottom weld width is unchanged with the increase of the welding current. With the welding speed decreasing, both the top and the bottom width increase, and the internal porosities decreases. Under the condition of laser power of 6 kW, welding current of 180 A, welding speed of 4 m/min and wire feeding rate of 4 m/min, the joint with good formation and few welding defects is obtained. Weld cross section is characterized by the wide top weld width and narrow bottom weld width. The microstructure of the joint is composed of equiaxed grain zone, columnar zone and equiaxed dendrite zone from the fusion line to the center of weld. The sizes of the grains and equiaxed dendrites from the top to the bottom are gradually reduced along the weld centerline. The fusion zone hardness is lower than that of the base metal, which indicates that the soften zone is occurred in the joint. The average tensile strength of joints is 369.8 MPa, which is approximately 83% of the base metal. And the extension rate is about 4%. The tensile fracture occurs in the weld zone, and the fracture morphology is distinctly ductile characteristics.