Abstract: Butt welding experiments of Mg to Al alloy filling with Zn wire were carried out by tungsten inert gas (TIG) welding. The welding joints were investigated and tested by metallography microscope, electronic probe micro-analyzer (EPMA), universal mechanical properties testing machine. The results indicated that the aluminum alloy 6061 and the magnesium alloy AZ31B was jointed with a good surface forming. The welded joints are mainly composed of MgZn₂,the zinc base solid solution and the aluminum base solid solution, there are not the obvious transitional layer between welded seam and aluminum base metal and the transitional layers which approximately 20- 100μm between welded seam and magnesium base metal. The hardness of the weld seam is higher than that of the base metal aluminium alloy 6061 and magnesium alloy AZ31B. The tensile strength of the butt joint is 75 MPa.