Abstract: The bolt is used more and more as a support tool, and the defects such as crack, corrosion, hole and so on will appear in the long term use.As a non-touch detection technique, magnetic ultrasonic technology has a wide application prospect in nondestructive testing of bolt.In order to overcome the electromagnetic ultrasonic guided wave stable, multi-mode, easy dispersion, echo noise and other issues, taking the electromagnetic ultrasonic testing of bolt as an example, a signal acquisition and analysis system is designed.The system transfers the collected signals to the host computer in real time through the acquisition card, and uses LabVIEW and MATLAB mixed programming to process the signal, so as to reduce the noise’s interference to the signal and improve the signal-to-noise ratio.The experimental results show that the system uses the improved Hilbert transform method can improve the signal to noise ratio, the transmission performance is good, and the signal can be collected and analyzed.