Abstract: In accordance with the electromigration of alloy interconnect in integrated circuits, the electric-thermal coupling analysis was performed for the electromigration process of Al-Si alloy interconnect with finite element analysis software ABAQUS. The relationship of the current density with the potential gradient, heat flux, and the total energy of interconnect was analyzed. The influence rule of the different dimensions on the electromigration failure of Al-Si interconnect was researched. The results indicated that both the maximums of potential gradient and heat flux concentrate on the narrow position of the interconnect. With the increasing current density and testing time, the potential gradient and heat flux increases. The changing trend of the total energy of interconnect sharp by drops firstly, and then rises to an equilibrium value with the time increases. The heat flux decreases with the width of interconnect increasing. If the width of interconnect is lower than 2μm, the failure possibility will increase dramatically for the SWEAT model in this paper.