Aimed at the shortages of existing service migration strategies, a proactive service migration model based on network survivability situation awareness is proposed. First, network survivability situation awareness is evaluated by using intrusion detection and failure detection timely, and under these circumstances, a service migration trigger mechanism based on network survivability situation awareness is designed. Then, a new concept "mainlysecondary server" is proposed, and service migration model is found combining directional and random ways, and correlative algorithm is researched. The results show that this service migration model improves not only survivability, but also reduces service break off time largely. And at the same time, this model is the guarantee of continuous and trusty run of service under conditions that something unexpected happens suddenly.