Abstract: This paper proposes a clustering algorithm for wireless sensor networks with the goal of helping the cluster-based intrusion detection schemes to detect malicious attackers.It partitions the whole network into a set of clusters with each cluster sensing a similar phenomenon.The sensors within the same cluster are physically close to each other.This feature insures that the intrusion detection schemes can identify anomaly nodes more easily and can achieve a lower false alarm rate and a higher detection accuracy rate than the existing detection schemes.At the same time,it can also make innetwork processing simpler,so it can reduce the node's power consumption and prolong the network lifetime.