Abstract: As the core of Internet of Things (IoT), Wireless Sensor Networks (WSNs) have received widespread concerned and widely used for different scenes. However, WSNs usually consist of nodes with limited energy; moreover, it is not possible to supply additional energy. Furthermore, insecure network nodes will increase the overall energy consumption and thus, how to effectively and accurately evaluate whether the status of the node is security or not becomes much more paramount. In this study, we propose anew security assessment architecture of WSNs based on energy detection. Compared with the previous one, our method is energy-efficient. The main contributions are as follows. On the one hand, the energy information of nodes in our architecture is being transferred to the cluster-header and then the security assessment method is only performed by the cluster-header, therefore, it not only reduces the transmission cost and network delay but also reduces the calculation times of each node. On the other hand, we introduce the Euclidean distance method for the security assessment and then divide the state of nodes into two sections according to the normalized result, thus it reduces the cost of further determine. Furthermore, although, different sensors differ from the detailed energy parameters, we give the generic value of security section by extended analysis.