针对覆层测厚仪在实际应用中往往出现测量不准、误差较大的问题，探讨基于磁感应测量原理、电涡流测量原理的覆层测厚仪的特殊性，分析了影响测量结果的诸多因素。对覆层测厚仪在测量时的各种校准方式作了较为系统的论述，强调仪器校准方式和基体选择的重要性，提供减小测量误差和提高测量效率的对策，对覆层测厚仪在测量时的现场校准和应用仪器正确测量具有实际指导作用。

Aiming at the inaccuracy and bigger error of coating thickness measuring instrument in actual application, this papper discussed the particularity of the measuring instrument for coating thickness based on the magnetic induction measuring principle and the eddy current measuring principle, analyzed influence factors to measurement result, and elaborated systematically on various kinds of calibration of the measuring instrument for coating thickness. The importance of the calibration mode and the matrix choice was emphasized, and the countermeasures to decrease the measurement error and improve the measuring efficiency were provided. It can be used to guide the field calibration of measuring instrument for coating thickness practically when measuring.