To meet the on?site in?situ calibration requirements of precision data collectors used in aircraft engine test benches, a comprehensive in?situ calibration system for data collectors has been developed. A low thermoelectric potential scanning switch was designed, and the data collector calibration software was developed for controlling multifunctional calibration sources, low thermoelectric potential scanning switches, and precision data collectors to achieve on?site in?situ calibration. The low thermoelectric potential path switching technology was used to automatically convert and collect multiple signals. Automated and parallelized execution of calibration programs was realized through multi?threaded calibration technology. The application effect of the in?situ comprehensive calibration system for aircraft engine test bench data collectors was verified through experiments. The results showed that the accuracy of the system met the requirements, and the time required to calibrate a single data collector using the system was only 3 hours, which was more than 6 times more efficient than traditional manual calibration methods. This system provides strong support for achieving efficient, convenient, and on?site calibration of multi?channel data collectors, and provides important reference for the research of in?situ automation calibration technology for other measuring equipment.