在现代民主社会中，媒体是社会正义之心理氛围和文化环境的建构者，它深刻地影响着公众对于国家行为正义与否的判断。本文以罗尔斯的正义理论为立论依据，认为在“棱镜门”事件中，媒体应明晰国家利益与社会正义的关系。以国家利益为借口掩人耳目、隐瞒权力滥用、置公民隐私权于不顾的做法有悖于媒体看护公众利益的天职，无助于社会正义之现实环境的建构。媒体可通过自我监管、强化正义观念、规范编辑加工手法、深化专业主义来建构社会正义的媒介环境，实现社会进步的边缘突破效能，进而维护社会正义的现实环境。

In modern democratic society, media is the modeler of social justice’s social mentality and culture context, which influence the public’s judgments on whether an act of state is justicial. Based on the theory of justice from John Rawls, This paper discusses western media reports about PRISM. It points out that media should comprehend the relation between social justice and national interests. If media insist on national interests and ignore citizens' privacy, they couldn’t be responsible for the public. Media may implement self-censorship, strengthen the conception of justice, regulate news editing and intensify professionalism to construct a media environment of social justice and maintain the actual environment of social justice.