Aimed at the remarkable characteristics of power restriction on wireless sensor networks, it is essential to resolve the issue on effective power management. Currently,plenty of research work runs short of integrity because it only considers powersaving from one of the following techniques such as the topology control mechanism, the rooting protocol or the data aggregation algorithm, but not to measure the power consumption of the whole network. With the introduction of mobile agents, it discusses the power management of the sensor networks from several points such as topology control and cluster forming, and data collection. Some novel algorithms based on mobile agents for power management are proposed. Based on simulation and  performance analysis on power consumption, balancing the communication flows and the whole networks’ lifespan, it analyzes the advantages, disadvantages and feasibility of these algorithms.