Key nods in micro-blog communication play a critical role in determining the amount and trend of information. This article focused on 7584 micro-blog posts of 30 key network public opinion cases between 2011 and 2012,and revealed the 2158 key nods and the corresponding influential factors,which showed that there were different key nods with varying impact. The top 9 popular key node IDs (0.41%) were commented and forwarded up to the 20% amount of total number of comments and forwards. The result indicated that the speed of report time on public events by key nods,the types of key nods and characteristics of posts significantly influence the amounts of comments and forwards. In contrast,number of fans have little impact on the amount of micro-blog's comments and forwards. It is suggested that we should pay great attention to the role of key nodes of micro-blog communication,especially the core key nods,and guide the public opinion of by the key nods. <<