Abstract: The problem of secure routing for MANET (mobile ad hoc network) is studied. Analyzing the advantages and disadvantages of intrusion detection and secure routing policies, an ECC-based secure routing algorithm for MANET is presented and implemented according to the special secure routing requirements of the MANET. The algorithm has obviously the advantages of those of the on-demand and table driven routing policies such as low energy consumption, short delay and high delivery rate etc. The signature and authentication based on ECC are introduced in the process of routing to exclude the malicious nodes from joining the route, which can ensure the security of the route, the integrity of data and non-repudiation. The performance of the algorithm presented is analyzed with NS-2, and the simulative results show its high efficiency.