摘要自20世纪90年代中国接入互联网络以来，网络逐渐实现了社会化，并作为“第四媒体”发挥着强大的舆情表达和传递功能。在公共危机事件发生、发展和变异过程中，因事件衍生的新闻报道、网民态度和观点等网络舆情在网络中形成扩散态势和井喷效应,并且因日益分化的网民、多样媒体等积极作为，公共危机事件网络舆情演变具有了不确定性和复杂性的特点，给公众认知以及政府引导公共危机事件网络舆情带来了极大困难。围绕公共危机事件发生后网上呈现的各种舆情，舆情产生的影响因素呈现的发展态势和规律等问题，本文以公共危机事件网络舆情为研究对象，以网络舆情演变为核心，运用生命周期理论，将公共危机事件网络舆情演变分为孕育、扩散、变换和衰减四个阶段，并结合7·23温州动车追尾事故网络舆情，认识和掌握复杂的网络舆情产生和变化规律，对公共危机事件网络舆情演变过程研究起到促进意义。【关键词】网络舆情舆情演变公共危机事件AbstractSincethe1990sChinahasinterconnectedwithnetwork,thenetworkhasrealizedsocializationgradually,anditisplayinganincreasinglyimportantfunctionforpublicopinionsexpressionandtransferasthefourthmedia.Inprocessoftheoccurrence,developmentandvariationofanunexpectedevent,thepublicopinionisformingthediffusionsituationandblowouteffectonaccountofthecoverageofmedia,theattitudeandviewofnetizenswhichderivedfromanunexpectedevent.Withtheincreasinglydifferentiatednetizensandmultiplemedium,theevolutionofthepublicopinionsofunexpectedeventsisnowpresentingthecharacteristicsofbeinguncertain,complexandfluctuantwhichmakeitdifficultforthepublicawarenessandgovernmentguidanceofthepublicopinions.Whatkindofpublicopinionswillshowaftertheoccurrenceofunexpectedevents,andwhatfactorsareplayinganimportantroleandwhattendencyandrulesthepublicopinionswillpresent?Focusingonthesequestions,thispaperaimsatstudyingthepublicopinionsontheInternetandemphasizesontheevolutionofthem.Byemployingthetheoryoflifecycle,thispaperdividestheevolutionofpublicopinionsofunexpectedeventsintofourparts,thatis,breeding,diffusion,transformationandattenuationandeverypartwillbediscussedindetails.KeywordsPubliccrisiseventsPublicOpiniononNetworktheEvolutionofPublicOpinion目录摘要..........................................................................................................IAbstract.....................................................................................................................II第1章绪论....................................................................................11.1研究背景....................................................................................11.2研究意义....................................................................................11.3国内外文献综述..............................................................31.3.1国外文献综述.....................................................................31.3.2国内文献综述.....................................................................41.4研究内容和方法..............................................................51.4.1研究内容....................................................................................51.4.2研究方法................................................................................5第2章相关概念及理论基础........................................72.1相关概念....................................................................................72.1.1互联网与网络传播.......................................................72.1.2舆论、舆情与民意.......................