Energy constraint is important issues in wireless sensor networks. This paper proposed a strategy for optimizing the placement of mobile sensor nodes, and energy metric of communication is presented for energy efficiency. The strategy can meet coverage and energy requirements, providing flexibility and adaptability for different energy constraints. Dijkstra?s algorithm is utilized to obtain the optimal paths from which energy metric is derived. Dynamic power management is used to optimize the transition of sleep states and serve system energy. Collaborative sensing mechanism is adopted in the network for mobile target tracking. During collaborative tracking procedure, tradeoff between coverage and energy consumption is achieved by optimizing both metrics and adjusting the metric weight of optimization. Simulations of mobile target tracking are executed to verify that energyefficiency is enhanced by deployment optimization strategy and dynamic power management mechanism.