Abstract: In this paper, an energy-efficient cluster-based data gathering protocol (ECDGP) is proposed.ECDGP uses a new clustering algorithm based on belief degree for clusterhead election.Furthermore, ECDGP selects the active nodes according to the demand of network coverage.By controlling the number of active nodes in a cluster, ECDGP reduces energy consumption and prolongs the network lifetime.Simulation results have shown that ECDGP significantly outperforms the traditional clustering routing algorithms in terms of energy consumption and network lifetime.