This article explores the application and impact of Niklas Luhmann’s theory of social systems in journalism research. It begins by outlining the basic contours of Luhmann’s systems theory，particularly its analysis of the mass media system，emphasizing how media achieves self-production and reproduction of communication through technological means. The article then discusses the acceptance of Luhmann’s theory in German journalism research in the 1990s，noting that systems theory offers a new perspective for understanding the uniqueness of the news system and its social functions. In the 2010s，the application of systems theory expanded to more countries，becoming an important tool for understanding changes in the news industry in the digital age. Although Luhmann’s theory is popular in the field of journalism studies，there are also misunderstandings and limitations in its application. The article concludes that there is still room for further exploration and application of Luhmann’s theory in the epistemological discussion of journalism research. Overall，systems theory has strengthened the in-depth understanding of the mechanisms of the news industry and its social role，contributing significant theoretical support to the evolution of journalism research.