Abstract: As one of the important processing performance indicators of the equipment, the system accuracy of the heat treatment equipment needs to be regularly tested to ensure the quality of the product’s heat treatment and the reliability of the vacuum recorded in the production data. However, the current heat treatment equipment is prone to various problems in the daily use process, resulting in the system accuracy index data being out of whack and unable to meet the requirements of the relevant standards. This paper describes in detail the process of solving a case of precision error of a vertical real air quenching furnace system, analyzes the composition of the system accuracy error theoretically, measures the accuracy error data in all aspects on site, carries out electrical system transformation and instrument accuracy calibration, and improves the system accuracy of the equipment to meet the requirements of equipment use.