Abstract: This paper, considering security threats faced by the typical LEACH protocol, proposes a novel effective solution, i.e.SZM-LEACH (secure zone-spanned multi-hop routing) for WSN.The main idea is to build the secure cluster-heads table which is based on partition autonomy, and to establish secure route by means of key management in route discovery process.The simulation experiments demonstrate that the proposed mechanism improves the performance of cluster-based routing significantly, in terms of data loss caused by malicious node, as well as network lifetime and energy consumption.