Abstract: The "grand classroom" in practical education serves as a vital bridge connecting the "educational field" with the "social field" in building a strong education nation in the new era. Grounded in historical logic and structured through a "three-dimensional framework", this study systematically traces the evolution of practice education from ancient "unity of knowledge and action" to contemporary "holistic education", revealing its historical progression from instrumental rationality to value rationality and ultimately ecological rationality. Focusing on the contemporary context and drawing on the backdrop of building a leading educational nation and digital transformation, this paper elucidates the groundbreaking advancements of the "grand classroom" in terms of innovation in educational objectives, transformation of implementation pathways, and upgrading of the evaluation system, addressing practical needs, the research constructs implementation pathways through three dimensions of individual development, educational innovation, and social service. This study aims to provide theoretical references and actionable guidance for optimizing the practice education system, helping resolve current challenges in its implementation.