Abstract: Ceramic-metal brazed joints are widely used in high-reliability electronic packaging and vacuum devices, and they usually undergo periodic temperature changes during service. Al₂O₃-4J33 metal is a typical sealing structure, which has a thermal expansion coefficient difference. The change in temperature causes significant thermal stress within the joint region, which may has certain impact on the fatigue performance and service stability of components. To study the evolution laws of microstructure and mechanical properties of the brazed joint after multiple thermal cycles, a standard Al₂O₃-4J33 brazed joint component was designed, and the thermal cycling tests ranging from 400 to 1500 cycles were conducted. The results demonstrate that the joint microstructure exhibits no remarkable change after thermal cycling, and the mechanical properties of joints remain nearly identicalbefore and after thermal cycling. The fracture occurs mainly at the interface between brazing filler and ceramic metallization layer. Simulation results show that when the thermal cycle temperature is -30 ℃ to 150 ℃, the toughness damage of joints stop rising obviously once a certain number of cycles are reached.