The research status of access control models for online social networks was analyzed and summarized. The key problems and challenges were also pointed out, and some development trends and future research directions was proposed. Along with the explosive development of online social networks, problems such as data sharing and privacy preservation are gradually grabbing the attention of the public. As information security mechanism, traditional access control models are incompetent to meet the security requirements under the complex circumstances of online social networks. Recent years, research on access control models for online social networks is becoming a hot topic and many new access control models have been proposed based on different perspectives.