Abstract: By comparing spread mechanism of infectious diseases with information transmission mechanism，this paper presents a mathematical model of information transmission mechanism in BBS.By modeling changes of the number of posts on topics in BBS，it analyzes features of information transmission mechanism in BBS，and utilizes actual data to illustrate and validate the features.The experimental results indicate that，although a lot of netizens are attracted by BBS，they are only interested in some topics and participate in the discussion；the growth rate of the number of posts on most topics（94.9%） increases first and then decreases to 0 while the growth rate of the number of posts on a few topics（5.1%） directly reduces to 0.These findings are helpful to understand information transmission mechanism in BBS and are instructive to control and manage the information transmission in BBS.

Key words: information transmission mechanism, social network, social cognition, social intelligence

摘要： 通过比较传染病传播机制与信息传播机制，提出BBS中的信息传播机制模型。通过对BBS中帖子数量变化规律的建模，分析了BBS中信息传播模式的特征，并使用实际数据说明BBS中的信息传播模式。实验表明：BBS可以吸引大批的用户参与，但用户只对部分话题感兴趣并参与讨论；绝大多数话题（占94.9%）帖子数的增长率先增加再减小直至为0，而少量话题（占5.1%）帖子数的增长率直接减小至0。这些结论有助于认识BBS的信息传播机制，对控制和管理BBS的信息传播有启发意义。

关键词: 信息传播模式, 复杂社会网络, 社会认知, 社会智能