Abstract: With the increasing popularity of social networks, user data as well as analysis results from social networks have become extensively utilized and the extensive sharing, deep mining and analysis of data have brought about unprecedented challenges regarding privacy breaches. To tackle privacy issues in social networks, researchers have proposed a number of privacy-preserving techniques as well as techniques to achieve a good balance between data sharing and privacy protection. First,social networks and privacy-preserving techniques were briefly reviewed. Subsequently, privacy-preserving technologies oriented towards information content, graph structure, and both information content and graph structure, were reviewed respectively. Following this, metrics for evaluating privacy-preserving technologies in social networks were reviewed, including attack and threat resistance, and privacy utility. Finally, challenges for future work and future research directions were also discussed.