Abstract: To address safety hazards caused by sudden faults during the construction of medium-voltage to low-voltage substations, this paper proposes a substation construction site monitoring model based on a digital twin dynamic data acquisition system. The model integrates real-time three-dimensional geometric information from Building Information Modeling (BIM) with operational data from the Supervisory Control And Data Acquisition (SCADA) system to build a digital twin system featuring bidirectional data interaction. This approach overcomes the limitation of traditional static BIM models that cannot dynamically reflect equipment status, enabling safety monitoring, predictive maintenance, and multi-parameter collaborative analysis on the construction site. Experimental results from a 20kV substation construction site demonstrate that the system successfully achieves real-time monitoring of construction safety equipment, with a detection accuracy of 0.964 for power construction violations. The model realizes digital twin implementation with a bidirectional data communication mechanism, enabling real-time linkage between the model and physical entities to support system feedback control and closed-loop regulation. This model effectively improves construction safety of substations, provides innovative solutions for intelligent management, and lays a technical foundation for the industry's transition toward digitalization and dynamic