Wireless Sensor Networks (WSNs) are composed of a number of resource-constrained sensor nodes which are often deployed in unattended environments. Therefore, WSNs easily encounter a variety of physical attacks. In this paper, we focus on one of physical attacks known as node replication attack, where an intruder randomly captures a legitimate sensor node, and collects all secret element. Then an intruder inserts the secret element in his malicious sensor nodes and deploys the malicious sensor nodes into the network. An intruder can use malicious nodes eavesdrop on the communication of other sensors, or inject false data reports that make a server misjudge. In recent years, detecting node replication attack is an important task in sensor network area. In our survey, we analyze previous research and demonstrate contributions of the existent literatures.