为探究突发群体事件各阶段的现象、动因和突变点等演化问题,通过剖析突发群体事件影响因素,将事件影响因素分为内在动因和外在诱因,以平息和爆发2种状态作为突发群体事件演化的趋势,构建突发群体事件演化模型,根据该模型解释突发群体事件各阶段的演化现象,找到突变点,分析演化趋势。结果表明:突发群体事件在内在动因和外在诱因的综合作用下,事件发展由量变到质变演化的3个层级阶段,其中,突变点对突发群体事件爆发起决定作用。 In order to explore the evolvement of phenomena, motives and mutation points in various stages of sudden mass incidents, this paper analyzes the influencing factors of sudden mass incidents and divides the influencing factors of the incidents into intrinsic motivation and external inducement to subside and erupt two states According to the model, the evolvement phenomenon of sudden group events is explained, the mutation point is found, and the evolution trend is analyzed. The results show that under the combination of internal motivation and external motivation, the events of sudden group events change from quantitative to qualitatively three stages, in which the mutation points play a decisive role in the burst of sudden group events.