本文分析了有关南海领土冲突国内公众舆情的844个问卷数据，认为南海领土冲突的国内公众舆论具有 “强群体极化”与 “弱群体极化”的区别。南海领土冲突的公众舆论具有一定程度的自相矛盾性与非理性特征。在新媒体时代，公众舆论对南海问题决策形成“堤坝”效应。公众舆论对外交决策的影响要通过网络舆论和大众传媒的转化，这具体表现在公众认为个人对南海问题决策的影响微乎其微，但是通过大众媒体则可以在一定程度上影响外交决策。南海领土冲突公众舆论的“群体极化”、自相矛盾性和非理性等特征对南海决策形成较大的压力，这需要政府考虑在新媒体环境下，如何更好引导公众舆论，疏导民族主义情绪，使公众舆论与南海决策形成一种良性的动态平衡。

By analyzing 844 questionnaires on public opinion of the South China Sea territorial conflict, This paper believes that domestic public opinion of the South China Sea territorial conflict has the differences of strong group polarization and weak group polarization. Public opinion on the South China Sea has the characteristics of self-contradiction and irrational part. In an era of new media, public opinion has a “dike” effect on the decision making of the South China Sea. If public opinion wants to affect foreign policy decision making, it needs to do it by the way of network and media. The public believe that individual almost cannot directly affect decision making of the South China Sea, but he can affect the latter to some extent by media. The characteristics of group polarization, self-contraction and irrational part of public opinion put great pressure on the decision making of the South China Sea. The government should consider how to better manage public opinion, allay nationalism, thus keeping a good homeostasis between public opinion and decision making of the South China Sea.