To explore the relationship between the parameters of spindleholder and holdertool interfaces and the stability of end milling, effect of parameters of spindleholder and holdertool interfaces on stability Lobe diagram was studied, which was based on parameter identification of spindleholder and holdertool interfaces and 2DOF dynamic model of end milling. The result shows that linear stiffness of spindleholder and holdertool interfaces is the most influential factor on stability lobe, and other interface parameters has some effect of different degree. Compared with spindleholder interface parameter, holdertool interface parameter especially rotational stiffness has greater influence on stability. 