Traffic obfuscation technology is one of the most commonly used techniques in censorship-circumvention systems. In order to improve the recognition accuracy and supervisory ability of network traffic, much attention has been paid to the recognition and tracking of obfuscated traffic. Through in-depth analysis of three main traffic confusion technologies, such as randomization, mimicry and tunneling, this paper compares the technical framework, concealment, ease of use and application scenarios of the traffic confusion technologies. In addition, the paper reviews two types of recognition technology:deep packet inspection and machine learning, and compares their recognition accuracy. Furthermore, it analyzes and compares two types of traffic tracing technology:passive and proactive correlation. Finally, it discusses the identification and trace technology development trends of obfuscation traffic.