Abstract: In this paper, a measuring device for measuring the thickness deviation of feeler gauge is designed to address the problems of the cumbersome and inefficient measurement process, and the structure and working principle of the measuring device are described in detail. Through the uncertainty assessment of the thickness deviation measurement results of the feeler gauge and the comparison with the length measuring instrument, it is verified that the measurement results of the measuring device are accurate and reliable and can meet the requirements of traceability.