Background <p>The high incidence, significant morbidity, and substantial economic burden of deep vein thrombosis (DVT) in patients with aneurysmal subarachnoid hemorrhage (aSAH) have rendered it a pressing global public health issue. Our previous research has demonstrated that evidence-based practices can effectively reduce the incidence of DVT among these patients; however, ensuring the sustained, high-fidelity implementation of such practices in routine care remains a significant challenge. This study aims to explore the barriers to the sustainable implementation of an evidence-based DVT prevention program for aSAH patients, to inform strategies that support its long-term integration into clinical practice.</p> Methods <p>A qualitative descriptive study was conducted from July to October 2025. An interview outline was formulated based on the Consolidated Framework for Implementation Research (CFIR). A purposive sampling method was employed, adhering to the principle of maximum variation, to conduct semi-structured interviews with medical staff from the neurosurgery department and the neurosurgery ICU of two tertiary grade A general hospitals in Nanchang City. The data were analyzed using a directed content analysis.</p> Results <p>A total of 14 eligible medical staff participated in this study, comprising 3 head nurses, 6 clinical nurses, 3 doctors, and 2 rehabilitation therapists. Five themes and 14 sub-themes were identified: (1) Characteristics of the intervention, which included unclear or unquantified relative advantage, challenges of scheme complexity and adaptability, and cumbersome documentation requirements; (2) External environment, encompassing lack of patient and family collaboration; (3) Internal environment, characterized by shortage of human and equipment resources, weak implementation atmosphere and leadership participation, absence of organizational incentive and reward and punishment mechanisms, insufficient learning atmosphere, and lack of institutionalized multidisciplinary collaboration mechanisms; (4) Individual characteristics, which involved persistent gaps in knowledge and awareness and unwillingness to change; (5) Implementation process, marked by inadequate planning and mobilization, the execution process lacks consistency and fidelity, and lack of reflection and evaluation mechanisms.</p> Conclusions <p>This study, conducted from the perspective of clinical medical staff and guided by the CFIR framework, explores the barriers influencing the evidence-based practice of DVT prevention in patients with aSAH. It provides a theoretical basis for nursing managers to formulate effective implementation strategies and promote the clinical integration of evidence-based practice programs. This will effectively overcome the barriers to evidence-based practice, enhance the quality of nursing, and ensure patient safety.</p> Clinical trial number <p>Not applicable.</p>