Abstract: In response to the urgent demand for high-precision detection technology in the national new quality productivity, the current non-contact detection method for shaft diameter has problems such as low detection accuracy and efficiency. This paper focused on the size detection of shaft components based on electromagnetic induction. Firstly, the three-dimensional simulation was used to analyze the variation law of spatial magnetic induction intensity of shaft components after applying high-frequency current. The maximum value of magnetic induction intensity was extracted and a mathematical algorithm was established based on the shaft diameter. The detection point was determined by the maximum value of magnetic induction intensity in the spatial horizontal direction. Then the impact of current magnitude and frequency changes on magnetic induction intensity was analyzed, excitation signal parameters were optimized to improve detection efficiency. Finally, by building a test platform to complete the inspection of shaft components, the comparative analysis results showed that both the measured and calculated values were within the allowable error range, and the relative error of the calculated values did not exceed 0.05%, meeting the accuracy requirements and laying the foundation for the design, development, and application of new detection equipment in the future.