Friction stir spot welding–brazing process was used to connect 2A14 aluminum alloy and AZ31 magnesium alloy. The microstructure, chemical composition and phase composition of the joints with different parameters were studied by scanning electron microscope, energy dispersion spectrum and X–ray diffractometer. The tensile and shear properties of the joint were tested by electronic universal testing machine. The results show that the stir zone is mainly composed of Al–Mg intermetallic compounds and a small amount of MgZn phase and MgZn₂ phase. The thermalmechanical affected zone is mainly composed of Zn–rich solid solution and Mg₇Zn₃ phase. The zinc solder near the aluminum alloy in the heat affected zone did not react with other elements, while the zinc solder near the magnesium alloy reacted with magnesium to form Mg–Zn intermetallic compounds. When the pressure distance of the shaft shoulder is 0.5 mm and the rotation speed of the mixing head is 950 r/min, the tensile shear load of the joint reaches the maximum value 7.6 kN.