Energy problem is a key issue for the wireless sensor network with limited batteries. It’ s a good idea to select a head node for data aggregation to save the energy of data transmitting. However, many algorithms don’t consider the whole integrated network situation for head node selection. We proposed an energy efficient head node selection method for data aggregation. In this algorithm, three aspects were taken into consideration, which were the candidate head node’s single residual energy, the total energy spent in the network if this candidate head node is chosen, and the quality of balance of the residual nodes’ energy. To adapt the actual sensor nodes with limited memory and computing capacity, a simplified model is also introduced. Simulation results show that this new head node selection algorithm can achieve balanced energy consumption and prolong the life time of the network highly.