With the development of social network and the advent of big data era， personal information security is facing unprecedented challenges. Internet information privacy security has become an important issue in global Internet governance. This article， from the perspective of the relationship between Internet privacy and social networking， combs important network privacy security cases of 2017， analyses the potential threat of network privacy security， and the cause of network privacy infringement—including the complexity of network space， personal protection consciousness， legal policy system is not sound， frequent network malicious attacks， network security service system is not perfect. On this basis， this paper also puts forward the protection strategy of network privacy from the legal level， personal level， Internet service provider level and international level.