Abstract: 5049 aluminum alloy plates were brazed by using 4047 aluminum alloy as filler metal. The formation rules of intermetallic compounds in brazing process were predicted by means of thermodynamic model. The microstructure of the brazed joints was analyzed at different brazing temperatures(590-615 ℃) and holding times(5-30 min) by using scanning electron microscopy, and the shear strength and microhardness of the alloy were tested after brazing. The results show that the intermetallic compounds at the interface of the joint are AlFeSi phase and Mg₂Si phase when held at 600 ℃ for 5 min. As the temperature increases to 610 ℃ and the time extends to 30 min, the Al₁₅(Fe,Mn)₄Si₂ phase and the Mg₂Si phase appear in the brazed joint. The shear tests show that the optimum brazing parameters are 600 ℃ for 30 min and the shear strength is 40.7 MPa. The fracture shows the morphology characteristics of tearing ridges, and some grain boundaries have smooth fracture surfaces, which is consistent with quasi-cleavage and intergranular fracture.