Aiming at the shortcomings of a typical Low Energy Adaptive Clustering Hierarchy (LEACH) routing protocol, which randomly selects cluster heads (CHs) and sends data to the base station (BS) by single-hop, an improved effcient routing protocol, Leach-sub-muti, is proposed. In the process of electing CH, the protocol considers the energy of the node, the distance from the node to the BS, the density around the node, and so on. After the cluster is formed, the backup CHs in the cluster are selected according to the load of the CH nodes. In the data transmission stage, if there is a backup CH in the cluster, the nodes in the cluster send data to the CH firstly, and then when the energy of the CH node is lower than the average energy, the backup CH temporarily acts as the CH to forward data to the BS. This protocol allows normal nodes to forward data to the BS directly. When ordinary nodes forward data to the CH, the data can be forwarded by combining single-hop and multihop. Similarly, the data of the CH is also forwarded to the base station in the same way. MATLAB simulation experiments show that the optimized protocol sends more packets with less energy than the LEACH protocol, reducing the energy loss of nodes, and extending the life cycle of the entire network.