When users use social media，their concern about privacy doesn’t affect self-disclosure，this phenomenon is called “privacy paradox”. The current studies on the phenomenon focus on measuring the relationship of variables，lacking of the discussion that is based on the personal experience. This study interviews college students who use WeChat，observes the contents that they have posted on the circle of friends，and analyzes the characteristics of self-disclosure，awareness of privacy，privacy controls of users of social media. We find that college students post rich content，but it is limited in several aspects. When they disclose themselves on the social media，college students are aware of privacy and confident in their ability of privacy controls. It shows that what college students care about is not their personal information is stolen by third parties，but the change of original communication context. Users see the privacy as a right that personal information should be communicated correctly. The reason why users still express themselves when they concern on privacy is that they think they can control the communication path and range by setting up the WeChat，thus it answers the phenomenon of privacy paradox in social media.