We consider the maximum lifetime routing problem for target tracking sensor network. The goal is to find the optimal routing to not only maximize the lifetime of the network but also provide real-time data transmission services. We first propose a novel model to formally define the lifetime of target tracking sensor network by establishing the relationship between individual sensors and the whole sensor network. In this model, we derive the key factor in routing that determines the lifetime bound. Then, considering this factor, we discuss the implementation of an ant-based routing algorithm. Preliminary result demonstrates the appealing performance of our proposed scheme.