The occurrence of sudden natural disasters not only cause huge casualties and property loss to people can also cause psychological trauma. It may cause microblog public opinion when sudden natural disasters occurred. If the microblog public opinion can’t be guided，it could caus serious social impact，and even cause social group events. Therefore in this paper，we have chosen 21 21 cases to study，including microblogging public opinion data analysis，in the case of established screening criteria，microblogging public opinion 21 sudden natural disasters in selected produced in the source and time，systematic analysis carried out on the local laws of fluctuation. And the paper also has analysed the microblog public opinion’s main publication，publish content，and disaster rumors. At last the paper has made a reasonable guide and methods of effective control for the microblog public opinion，for this is not only a problem in the field of network communication，but also the whole society needs to discuss the issue