Online Collaborative Learning is typical developed and maintained through participants’ social interaction,and can be attributed to participation and dialogue between cognitive metaphor and participation metaphor.For this purpose,this paper firstly used social network analysis(SNA) method and analysed the dentisy of the interaction of the participants to evaluate participants’ participation rates.Secondly,we performed a centrality analysis to analyse the power distribution of the participants. Thirdly,we did a cohesive subgroup analysis to identify the solidarity of the participants and a role analysis to identify the social roles of the participants in the network. The findings showed that the density of interaction among participants was not high, and the teacher’s participation had a great influence on the participation of the group. There are, however,substantial differences in the participants' participation activities. The results also indicated that the power distributions among the participants weren't even,participants only interacted frequently with several core participants.The study further revealed that participants had different role positions in social space.