AZ31B magnesium alloys and 201 stainless steel are joined by laser welding-brazing process with Mg based filler. The welding characteristics including influence of processing parameters on weld appearance, mechanical properties and fracture behavior are studied. Results indicate that satisfactory appearance of welds without evident defects can be achieved by dual beam laser-brazing process with filler. A wide processing window is obtained. The tensile-shear test shows that fracture occurred at two places, weld seam and heat affect zone (HAZ) at the welding side of Mg alloys. The maximum shear strength can reach 193 MPa, which is 71% of that of Mg base metal. The microstructure observed indicates that seam and HAZ are weak parts, which results in failure of joint due to presence of coarse grains. Metallurgical reaction occurs at the brazing side, where reaction layer with thickness of 1~2 μm forms.