Abstract: In view of the problem that the quality of defect detection is not high in anchor bolt anchoring, this paper uses electromagnetic ultrasonic technology to complete the quality detection of anchor bolt.Firstly, PCDISP software is used to obtain the dispersion curve and determine the optimal excitation frequency.Then, COMSOL finite element simulation software is used to establish the three-dimensional model of anchor bolt anchoring, and the optimal parameters of bias magnetic field are set up.The effect of effective length of anchor, the depth of anchor bolt corrosion and the size of defects on the detection waveform is analyzed.Finally, a physical experiment platform is built to analyze the collected echo signal, and the experimental data verify the effectiveness of the numerical analysis results.The results show that the electromagnetic ultrasonic technology can effectively detect the effective length and defect position of the anchor when it is used in the anchor quality detection.