The survivability of defense system refers to the ability of the system to maintain or restore its defense performance to an acceptable level when the system is facing enemy attack damage or its own node failure. In order to measure and characterize the survivability of defense systems with different architectures， based on the combat confrontation scenario and from the ability of the system to build strike links， a new method of survivability measurement of defense systems is proposed. This method can be used to quantitatively characterize the survivability of traditional defense system and distributed defense system， and provide support for further distributed defense research and high survivability architecture design of defense system.