Wireless sensor networks (WSNs) are important application for safety monitoring in underground coal mines,which are difficult to monitor due to natural conditions.Based on the characteristic of limited energy for WSNs in confined underground area such as coal face and laneway,we presents an energy-efficient clustering routing protocol based on weight (ECRPW) to prolong the lifetime of networks.ECRPW takes into consideration the nodes' residual energy during the election process of cluster heads.The constraint of distance threshold is used to optimize cluster scheme.Furthermore,the protocol also sets up a routing tree based on cluster heads' weight.The results show that ECRPW had better performance in energy consumption,death ratio of node and network lifetime.