Electromigration is usually observed in metal conductive lines of electronics chips. However, under conditions of high temperature and high current density, electro-migration will also occur in thin film resistor material. The electromigration in a thin film resistor will cause resistance degradations and result in resistor opens.In this paper, electromigration failure mechanism in TaAl thin film resistor is discussed based on microstructural analysis. In addition, resistance degradations due to electromigration are characterized, and a model based on experimental data is generated to quantitatively describe this new phenomenon.