As a core link connecting the physical and virtual worlds, digital twin technology plays a pivotal role in the intelligent transformation of industry. In particular, it provides a new approach for safe and efficient production in the complex operating environments of the coal industry. This paper focuses on the de-velopment status, general key technologies of digital twin technology, and its application in the coal sector (taking hydraulic supports as a case study). First, it sorts out the conceptual evolution and cross-industry application characteristics of digital twin technology, and analyzes the current technical bottlenecks in terms of modeling accuracy, sensing reliability, communication real-time performance, and cross-system compatibility. Second, it systematically expounds the core principles and application status of the general key technologies of digital twin, including technical architecture, geometric modeling, mechanism modeling, communication, monitoring and prediction, and control. Finally, in response to the demands of the coal industry, a digital twin technical architecture for hydraulic supports is constructed, clarifying the physical entity optimization, virtual model construction, virtual-real interaction mechanism, and the whole-life-cycle management and control process. This research can provide theoretical support and technical reference for the practical application of digital twin technology in the coal industry, and con-tribute to the construction of smart mines and the intelligent upgrading of coal mines.