Safeguard mechanisms form the essential foundation for ensuring the digital transformation of human resource management progresses from short-term breakthroughs to sustained deepening. This study constructs a comprehensive safeguard system encompassing four dimensions: institutional, organisational, technological, and cultural. Centred on dynamic synergy as its core logic, this system provides a stable regulatory framework for transformation through institutional design; empowers implementing entities to enhance execution capabilities by leveraging organisational restructuring; establishes a robust material foundation through technological architecture; and fosters collective consensus on transformation via cultural shaping. These four dimensions do not operate in isolation but form a virtuous cycle: "institutional frameworks guide organisational behaviour; organisations deploy technological tools; technology facilitates cultural dissemination; and culture reinforces institutional commitment." Ultimately, this cycle assists enterprises in transforming fragmented digital practices into enduring organisational capabilities, thereby achieving the sustainable development of digital transformation.