This study examines prosecutorial argumentation strategies in complex criminal cases using a Critical Discourse Analysis (CDA) framework. Drawing on a corpus of 45 prosecutorial indictments from 2020–2025, the research investigates how language, intertextuality, and social context interact to construct legal legitimacy. The findings reveal that prosecutorial texts are not merely descriptive legal documents but function as strategic discursive instruments. At the micro level, linguistic features such as modal certainty, complex syntactic structures, and evaluative diction are systematically employed to construct an appearance of legal objectivity and certainty. At the meso level, intertextuality plays a central role in reinforcing argumentation through the integration of indictments, evidence, and judicial references, forming a coherent narrative structure. At the macro level, the study demonstrates that social context, particularly public exposure, significantly influences the intensity and moral tone of prosecutorial discourse. The study identifies four dominant argumentation strategies—framing, legitimacy construction, persuasion, and simplification—that operate in an integrated manner to influence judicial reasoning. Based on these findings, the research proposes an Integrated Prosecutorial Discourse Model, highlighting the interaction between textual, discursive, and social dimensions in shaping legal argumentation. Theoretically, this study extends the application of CDA by incorporating argumentation strategies as a central analytical component in legal discourse. Empirically, it provides a broader analytical generalization through a multi-document corpus. Practically, the findings contribute to improving transparency and critical awareness in prosecutorial practices. Overall, this study demonstrates that legal legitimacy is not solely derived from normative frameworks but is also constructed through strategic discursive processes.