Wireless sensor networks are open architectures, so any potential threat can easily intercept, wiretap and counterfeit the information. Therefore, the safety of WSN is very important. Since any single key system cannot guarantee the security of the wireless sensor network for communications, this paper introduces a hierarchical key management scheme based on the different abilities of different sensor nodes in the clustered wireless sensor network. In this scheme, the nodes are distributed into several clusters, and a cluster head must be elected for each cluster. Private communication between cluster heads is realized through the encryption system based on the identity of each head while private communication between cluster nodes in a same cluster head is achieved through the random key preliminary distribution system. Considering the characteristics of WSN, we adopt dynamic means called dynamic cluster key management scheme to deal with master key, so master key will be updated according to the changed dynamic network topology. For cluster head node plays a pivotal role in this scheme, a trust manage-ment system should be introduced into the election of the cluster head which will exclude the malicious node from outside the cluster, thus improve the whole network security. Wireless sensor networks are open architectures, so any potential threat can easily intercept, wiretap and counterfeit the information. Therefore, the safety of WSN is very important. Since any single key system can not guarantee the security of the wireless sensor network for communications, this paper introduces a hierarchical key management scheme based on the different abilities of different sensor nodes in the clustered wireless sensor network. In this scheme, the nodes are distributed into several clusters, and a cluster head must be elected for each cluster is realized through the encryption system based on the identity of each head while private cluster between in cluster nodes in a same cluster head; to deal with master key, so master key will be updated acco rding to the changed dynamic network topology. For cluster head node plays a pivotal role in this scheme, a trust manage-ment system should be introduced into the election of the cluster head which will exclude exclude the malicious node from outside the cluster, thus improve the whole network security.