<p>In order to achieve brazing of magnesium alloy, A new MgAlIn filler metal was designed by the phase diagram method, and the brazing of AZ31 magnesium alloy was realized by scraping brazing under the condition of flame heating. XRD SEM and EDS were used for phase and microstructure analysis of filler metal and interfaces, the results show that the filler was composed of Mg₁₂AI₁₇ matrix and granular and cobblestone-like α-Mg, where α-Mg is a solid solution rich in In and Al. The Vickers hardness of the filler metal is 153 HV, 176 HV and 146 HV respectively. The DSC test results show that the melting point of the filler metal was between 425℃, 444.8℃ and 452.4℃. The analysis of the interface shows that the interface organization consists of α-Mg and (α-Mg + Al₁₂Mg₁₇). With the increase of Al content in the brazing Material, the shear strength of the lap joint decreases from 85 to 80MPa. The fracture occurs at the interface, there are a large number of cleavage steps and a small amount of rock sugar particles on the fracture surface. The fracture mode is the mixed fracture of intergranular fracture and transgranular fracture,. Al₁₂Mg₁₇ phase is the main cause of this phenomenon.</p>