To elucidate the role and operating logic of science and technology journals in the advancement of national strategic agendas, this study constructs a systematic analytical framework grounded in their core functions. Against the backdrop of building a world-leading science and technology powerhouse and achieving high-level self-reliance in science and technology, China's science and technology journals are undergoing a profound transformation from "platforms for publishing scientific achievements" to "platforms for supporting national strategies". While national policies such as the "Action Plan for Excellent STM Journals" have significantly enhanced the international influence of Chinese journals, a structural contradiction persists between high-level policy promotion and the absence of systematic service mechanisms. Existing research predominantly focuses on the inherent functions of journals as knowledge carriers and academic communication media, treating their service to national strategies as an external value extension rather than an endogenous mechanism. To address this gap, this paper identifies four core functions of these journals, i.e., agenda setting, knowledge integration, transformation and diffusion, and dynamic assessment, which serve as the logical starting point and driving force for serving national strategies. Drawing upon representative cases, including the Bulletin of the Chinese Academy of Sciences, the Journal of China Coal Society, Optics and Precision Engineering, and the Journal of Natural Resources, this paper conducts an in-depth exploration of the intrinsic mechanisms and practical implementation pathways. The analysis identifies four principal mechanisms: (1) the "demand identification and targeted topic selection" response mechanism, which ensures research directions align with national strategic needs; (2) the "knowledge integration and collaborative linkage" empowerment mechanism, which provides theoretical support and intellectual backing for strategy implementation; (3) the "achievement catalysis and value transmission" driving mechanism, which accelerates the transformation of key core technologies into industrial applications; and (4) the "effect evaluation and strategy iteration" feedback mechanism, which constructs a closed-loop monitoring system to safeguard the sustainability and adaptability of strategic development. On this basis, the study proposes an integrative theoretical framework that articulates the linkage among "core functions—service mechanisms—strategic support", systematically revealing how these journals can achieve comprehensive support for national strategies through the synergistic operation of these mechanisms. Furthermore, this paper proposes actionable implementation pathways across four dimensions: (1) establishing a strategic perception and targeted planning demand response system; (2) building a cross-boundary integration and knowledge co-creation empowerment ecosystem; (3) developing an achievement dissemination and industry linkage value transformation chain; and (4) improving an evidence-based assessment and decision consultation iterative feedback loop. Building upon these findings, this paper argues that these journals should proactively transcend their conventional positioning as passive disseminators of research outputs. Through systematic mechanism design and strategic resource integration, journals can evolve into pivotal nodes within the national innovation ecosystem, thereby realizing their strategic service value as "a minor player with a major role" in national development.