Abstract: To address the challenge of composite geometric parameter metrology for large infrastructure structures in complex environments, the limitations of traditional metrology technology—restricted to controlled environments, single parameters, and discrete points—make it difficult to meet the requirements of “comprehensive measurement, accurate measurement, and controllable traceability evaluation”. Introducing digital twin technology into the metrology field can effectively solve the problems of dynamic, continuous, and stable measurement of composite parameters and intelligent data processing, thereby enhancing geometric metrology under multi-dimensional, multi-parameter, and multi-environment coupling. This enables full-sample, multi-scenario digital metrological calibration. Firstly, measurement experiments were conducted using an indoor 80 m standard baseline to establish a multidimensional parameter database under standard scales. A thermo-mechanical-fluid-solid multi-field coupling mechanism model was constructed, revealing the virtual-physical mapping mechanism of composite parameters. Secondly, a three-dimensional multibody dynamics digital model was established. Mechanistic models, data-driven models, statistical models, and empirical knowledge were integrated to build a digital twin that fuses virtual and real aspects. Then, multiple characteristic hyperspheres of composite parameters were constructed using a deep support vector data description method. Based on different probability density distributions, the feature space was partitioned into corresponding regions for different parameters, achieving targeted identification of abnormal parameters and metrological traceability. Additionally, multidimensional sensitive feature vectors were extracted from anomaly-free metrological sample data. The generalized multi-kernel clustering analysis method was used to adaptively calculate neighborhood distances, evaluating the metrological accuracy level. Finally, the digital twin metrology method that integrates "calculation-measurement fusion and traceability-evaluation unity" is extended to a 1.2km three-dimensional outdoor standard baseline, providing a feasible preliminary solution and application approach for achieving digital precision metrology.