SNS (social networking services) is an important platform for Internet users to get knowledge and information, and users can share messages mutually via this platform. This kind of sharing can make user exchange and gain useful information to benefit themselves. However, in recent years, the crisis of stickness has appeared in SNS, which raised the attention of the social network industry. Relevant professionals explain that most users may gradually reduce the interest of sharing knowledge on SNS websites and applications and then give it up because the platforms utilize simple and uninterested methods to attract the users to participate actively on them. But factors influencing the knowledge sharing on SNS websites and applications should be identified clearly through researches. Sina Weibo is one of the largest SNS platforms in the world, and the researches on the factors influencing the knowledge sharing of users could be valuable for the issue.