Abstract: The lifetime maximization in wireless sensor networks (WSNs) was investigated. Network traffic and power consumption were analyzed, and an optimization model was proposed, which integrated power control and data aggregation. A decomposition algorithm was presented to solve the model by decomposing the model into sub-problems. The optimal transmission power, transmission rate and routing selection solution could be obtained via the subgradient. The simulation results showed that the data traffic can be reduced and energy consumption can be balanced on the basis of the proposed cross-layer design algorithm, and the network lifetime can be prolonged effectively.