Self-protection and protected by internet service provider are both accounting for information privacy security. This study focused on the attitudes and behaviors of social networking service(SNS) users toward individual information privacy, by using online questionnaire method to access 355 China’s SNS users, to investigate the relationship between privacy concerns, general willingness to self-disclosure, protective performance by selfassessment, and tweets sending behaviors in the social network. Findings indicate that users who send more tweets in their social networks often have higher willingness of self-disclosure, higher privacy concerns, and less network experience. Additionally, mediated by privacy concerns and general willingness to self-disclosure, SNS users’ protective performance based on self-assessment can positively affect their numbers of tweets sending. Our results show the existence of privacy paradox in social networking service. More specifcally, when SNS users think they have better performance in information privacy protection, they tend to think that they are more concerned about information privacy and will no longer suppress the tweet transmission in social networks. Furthermore, SNS users’ protective performance by selfassessment will also positively affect their general willingness to self-disclosure which is a strong determinant of their tweets sending behaviors.