Abstract: With the rapid development of the aerospace and high-end equipment manufacturing fields, the metrological assurance capability of specialized test equipment (such as large-scale comprehensive test rigs) has become key to ensuring product quality. The traditional off-site calibration mode presents problems such as long cycles and frequent disassembly and assembly, making it difficult to truly reflect the comprehensive measurement accuracy of the equipment under actual working conditions. Based on an analysis of the technological systems and application status of in-situ calibration domestically and internationally, and combined with the engineering practice of a typical multi-parameter comprehensive test rig in a specific project, this paper systematically reviews and designs in-situ calibration methods for various physical parameters, and proposes corresponding metrological design schemes. This study provides an engineering-feasible technical reference for the in-situ calibration of in-use test rigs, and also offers theoretical and practical guidance for the standardized design of newly developed test equipment in the future.