Anonymous networks aim to protect the user’s communication privacy in open network environment. Since Chaum proposed Mix-net, related work has been progressing in decades. Nowadays, based on Mix-net, DC-net or PIR, many anonymous networks have been developed, for various application scenarios and threat models by integrating multiple design elements. Beginning from anonymity concepts, this paper introduces the overall development of anonymous network area. Representative works and their design choices are classified and articulated. The characteristics of anonymous networks are systematically analyzed from the perspectives of anonymity, latency, bandwidth overhead, etc.