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Due to the special role of gauge blocks as length references, it is necessary to ensure their long-term data stability throughout their useful life. Their length measurements must be calibrated regularly, and by monitoring the trends in these data over time, failures can be effectively prevented. At present, the main method for calibrating gauge blocks is the contact-based measurement using a length measuring machine. High-precision grating length measuring machines are susceptible to influences such as instrument accuracy and environmental factors during the calibration process; therefore, to accurately determine the true value of a gauge block, it is necessary to analyze the actual causes of calibration errors. With the mature application of key technologies such as ultra-high precision guide rail technology, high-precision machining technology, high-precision temperature correction, high-precision grating technology, and intelligent software, accurate calibration of gauge blocks can be achieved through effective compensation methods and system error correction. The following describes the method for calibrating gauge blocks using the SJ5100 high-precision grating length measuring machine, analyzes the influencing factors of the detection methods, verifies through experiments, analyzes the main errors caused by the gauge blocks, and demonstrates the solutions. Schematic diagram of calibrating gauge blocks using a high-precision grating length measuring machine. Calibration flowchart. Analysis of calibration errors. Environmental factors: 1) Unstable laboratory temperature leads to rapid changes in the temperature of the gauge blocks, preventing the sensors from accurately reflecting their actual temperature ； Solution: Try to keep the laboratory temperature at which the calibration blocks are used within the range of 20±1°C/20±0.5°C, or monitor the ambient temperature to ensure it remains within an appropriate range during the calibration of the blocks. 2) The issue of environmental temperature gradients: The gauge blocks are placed on a workbench at a constant temperature. Due to the large size of the laboratory, significant temperature gradients exist, which result in a large difference between the temperature of the gauge blocks and that of the instruments, thereby causing temperature-related drifts. Solution: Maintain a constant temperature at the designated location (on the workbench, with a temperature that is close to that of the main instrument); the material temperature sensor should be attached to the surface of the gauge block, while the ambient temperature sensor should be placed near the measuring rod of the tailstock. Operation-induced errors: 1) The operator not wearing gloves caused body heat to be transferred rapidly to the gauge blocks, resulting in uneven temperature distribution among them ； Solution: Operate while wearing gloves properly, act as quickly as possible when making contact, and avoid touching the metal casing of the temperature sensor. 2) The adjustment position of the support pivot for the gauge block was not near the markings on that pivot, resulting in deformation of the gauge block’s support ； Solution: Clamp the gauge block using the alignment notch at its fulcrum to ensure the correct support position. 3) The dirt on the surface of the measuring cap has not been removed. Solution: Wipe the surface of the testing cap and probe with industrial alcohol, wait for a steady temperature after wiping before conducting the measurement. Instrument system error 1) Instrument repeatability and indication error. Solution: Use length measuring machines with different precision levels to calibrate gauge blocks of various grades.