Abstract: In this study, a novel energy-balancing unequal clustering protocol (EB-UCP) for wireless sensor networks is presented. EB-UCP achieves a good performance in terms of lifetime by unequal clustering and balancing the energy load among all the nodes. An unequal clustering algorithm from probability view is employed to form clusters. Clusters closer to the sink node have smaller sizes than those farther away from the sink node, thus cluster heads closer to the sink node can preserve more energy for the purpose of inter-cluster data forwarding. In addition, the distribution of sensor nodes is deployed according to the energy-balancing layered algorithm and therefore the energy consumption in every layer is nearly equal. Finally, an energy-efficient data transmission mechanism on basis of the above is proposed. Simulation studies show that EB-UCP leads to more uniform energy dissipation and enlarges the lifetime of networks than EEUC (Energy Efficient Unequal Clustering) and LEACH (Low-Energy Adaptive Clustering Hierarchy).