Security problem is an important issue for Wireless Sensor Network.The paper focuses on the privacy protection of WSN applications.Firstly,an anonymity enhancement tactic based on pseudonym mechanism is presented for clustered Wireless Sensor Network,which provides anonymity for both the sensors within a cluster and the cluster head nodes.Afterwards,an entropy based method is exploited to evaluate the degree of anonymity of our scheme.Further,simulation experiments are launched through NS2 platform to validate the anonymity performance.The theoretical analysis and empirical study imply that the proposed scheme based on pseudonym can protect the privacies of both the sensor nodes and the cluster head nodes,thus it can provide good anonymity forWSN applications.